985 lines
36 KiB
JavaScript
985 lines
36 KiB
JavaScript
/***********************************************************************
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A JavaScript tokenizer / parser / beautifier / compressor.
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https://github.com/mishoo/UglifyJS2
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-------------------------------- (C) ---------------------------------
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Author: Mihai Bazon
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<mihai.bazon@gmail.com>
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http://mihai.bazon.net/blog
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Distributed under the BSD license:
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Copyright 2012 (c) Mihai Bazon <mihai.bazon@gmail.com>
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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* Redistributions of source code must retain the above
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copyright notice, this list of conditions and the following
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disclaimer.
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* Redistributions in binary form must reproduce the above
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copyright notice, this list of conditions and the following
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disclaimer in the documentation and/or other materials
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provided with the distribution.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER “AS IS” AND ANY
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EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
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OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
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TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
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THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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SUCH DAMAGE.
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***********************************************************************/
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import {
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AST_Array,
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AST_Arrow,
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AST_Assign,
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AST_BigInt,
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AST_Binary,
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AST_Block,
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AST_BlockStatement,
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AST_Call,
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AST_Case,
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AST_Chain,
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AST_Class,
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AST_DefClass,
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AST_ClassStaticBlock,
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AST_ClassProperty,
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AST_ConciseMethod,
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AST_Conditional,
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AST_Constant,
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AST_Definitions,
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AST_Dot,
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AST_EmptyStatement,
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AST_Expansion,
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AST_False,
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AST_ForIn,
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AST_Function,
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AST_If,
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AST_Import,
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AST_ImportMeta,
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AST_Jump,
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AST_LabeledStatement,
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AST_Lambda,
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AST_New,
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AST_Node,
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AST_Null,
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AST_Number,
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AST_Object,
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AST_ObjectGetter,
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AST_ObjectKeyVal,
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AST_ObjectProperty,
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AST_ObjectSetter,
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AST_PropAccess,
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AST_RegExp,
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AST_Return,
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AST_Scope,
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AST_Sequence,
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AST_SimpleStatement,
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AST_Statement,
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AST_String,
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AST_Sub,
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AST_Switch,
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AST_SwitchBranch,
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AST_SymbolClassProperty,
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AST_SymbolDeclaration,
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AST_SymbolRef,
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AST_TemplateSegment,
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AST_TemplateString,
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AST_This,
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AST_True,
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AST_Try,
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AST_Unary,
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AST_UnaryPostfix,
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AST_UnaryPrefix,
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AST_Undefined,
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AST_VarDef,
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walk,
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walk_abort,
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_PURE
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} from "../ast.js";
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import {
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makePredicate,
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return_true,
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return_false,
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return_null,
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return_this,
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make_node,
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member,
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has_annotation,
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} from "../utils/index.js";
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import { make_sequence, best_of_expression, read_property } from "./common.js";
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import { INLINED, UNDEFINED, has_flag } from "./compressor-flags.js";
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import { pure_prop_access_globals, is_pure_native_fn, is_pure_native_method } from "./native-objects.js";
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// Functions and methods to infer certain facts about expressions
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// It's not always possible to be 100% sure about something just by static analysis,
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// so `true` means yes, and `false` means maybe
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export const is_undeclared_ref = (node) =>
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node instanceof AST_SymbolRef && node.definition().undeclared;
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export const bitwise_binop = makePredicate("<<< >> << & | ^ ~");
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export const lazy_op = makePredicate("&& || ??");
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export const unary_side_effects = makePredicate("delete ++ --");
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// methods to determine whether an expression has a boolean result type
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(function(def_is_boolean) {
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const unary_bool = makePredicate("! delete");
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const binary_bool = makePredicate("in instanceof == != === !== < <= >= >");
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def_is_boolean(AST_Node, return_false);
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def_is_boolean(AST_UnaryPrefix, function() {
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return unary_bool.has(this.operator);
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});
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def_is_boolean(AST_Binary, function() {
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return binary_bool.has(this.operator)
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|| lazy_op.has(this.operator)
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&& this.left.is_boolean()
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&& this.right.is_boolean();
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});
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def_is_boolean(AST_Conditional, function() {
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return this.consequent.is_boolean() && this.alternative.is_boolean();
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});
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def_is_boolean(AST_Assign, function() {
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return this.operator == "=" && this.right.is_boolean();
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});
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def_is_boolean(AST_Sequence, function() {
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return this.tail_node().is_boolean();
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});
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def_is_boolean(AST_True, return_true);
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def_is_boolean(AST_False, return_true);
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})(function(node, func) {
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node.DEFMETHOD("is_boolean", func);
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});
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// methods to determine if an expression has a numeric result type
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(function(def_is_number) {
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def_is_number(AST_Node, return_false);
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def_is_number(AST_Number, return_true);
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const unary = makePredicate("+ - ~ ++ --");
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def_is_number(AST_Unary, function() {
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return unary.has(this.operator) && !(this.expression instanceof AST_BigInt);
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});
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const numeric_ops = makePredicate("- * / % & | ^ << >> >>>");
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def_is_number(AST_Binary, function(compressor) {
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return numeric_ops.has(this.operator) || this.operator == "+"
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&& this.left.is_number(compressor)
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&& this.right.is_number(compressor);
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});
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def_is_number(AST_Assign, function(compressor) {
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return numeric_ops.has(this.operator.slice(0, -1))
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|| this.operator == "=" && this.right.is_number(compressor);
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});
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def_is_number(AST_Sequence, function(compressor) {
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return this.tail_node().is_number(compressor);
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});
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def_is_number(AST_Conditional, function(compressor) {
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return this.consequent.is_number(compressor) && this.alternative.is_number(compressor);
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});
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})(function(node, func) {
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node.DEFMETHOD("is_number", func);
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});
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// methods to determine if an expression is a 32 bit integer (IE results from bitwise ops, or is an integer constant fitting in that size
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(function(def_is_32_bit_integer) {
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def_is_32_bit_integer(AST_Node, return_false);
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def_is_32_bit_integer(AST_Number, function() {
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return this.value === (this.value | 0);
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});
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def_is_32_bit_integer(AST_UnaryPrefix, function() {
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return this.operator == "~" ? this.expression.is_number()
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: this.operator === "+" ? this.expression.is_32_bit_integer()
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: false;
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});
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def_is_32_bit_integer(AST_Binary, function() {
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return bitwise_binop.has(this.operator);
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});
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}(function (node, func) {
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node.DEFMETHOD("is_32_bit_integer", func);
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}));
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// methods to determine if an expression has a string result type
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(function(def_is_string) {
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def_is_string(AST_Node, return_false);
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def_is_string(AST_String, return_true);
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def_is_string(AST_TemplateString, return_true);
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def_is_string(AST_UnaryPrefix, function() {
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return this.operator == "typeof";
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});
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def_is_string(AST_Binary, function(compressor) {
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return this.operator == "+" &&
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(this.left.is_string(compressor) || this.right.is_string(compressor));
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});
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def_is_string(AST_Assign, function(compressor) {
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return (this.operator == "=" || this.operator == "+=") && this.right.is_string(compressor);
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});
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def_is_string(AST_Sequence, function(compressor) {
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return this.tail_node().is_string(compressor);
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});
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def_is_string(AST_Conditional, function(compressor) {
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return this.consequent.is_string(compressor) && this.alternative.is_string(compressor);
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});
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})(function(node, func) {
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node.DEFMETHOD("is_string", func);
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});
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export function is_undefined(node, compressor) {
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return (
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has_flag(node, UNDEFINED)
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|| node instanceof AST_Undefined
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|| node instanceof AST_UnaryPrefix
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&& node.operator == "void"
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&& !node.expression.has_side_effects(compressor)
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);
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}
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// Is the node explicitly null or undefined.
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function is_null_or_undefined(node, compressor) {
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let fixed;
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return (
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node instanceof AST_Null
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|| is_undefined(node, compressor)
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|| (
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node instanceof AST_SymbolRef
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&& (fixed = node.definition().fixed) instanceof AST_Node
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&& is_nullish(fixed, compressor)
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)
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);
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}
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// Find out if this expression is optionally chained from a base-point that we
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// can statically analyze as null or undefined.
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export function is_nullish_shortcircuited(node, compressor) {
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if (node instanceof AST_PropAccess || node instanceof AST_Call) {
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return (
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(node.optional && is_null_or_undefined(node.expression, compressor))
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|| is_nullish_shortcircuited(node.expression, compressor)
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);
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}
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if (node instanceof AST_Chain) return is_nullish_shortcircuited(node.expression, compressor);
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return false;
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}
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// Find out if something is == null, or can short circuit into nullish.
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// Used to optimize ?. and ??
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export function is_nullish(node, compressor) {
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if (is_null_or_undefined(node, compressor)) return true;
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return is_nullish_shortcircuited(node, compressor);
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}
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// Determine if expression might cause side effects
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// If there's a possibility that a node may change something when it's executed, this returns true
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(function(def_has_side_effects) {
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def_has_side_effects(AST_Node, return_true);
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def_has_side_effects(AST_EmptyStatement, return_false);
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def_has_side_effects(AST_Constant, return_false);
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def_has_side_effects(AST_This, return_false);
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function any(list, compressor) {
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for (var i = list.length; --i >= 0;)
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if (list[i].has_side_effects(compressor))
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return true;
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return false;
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}
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def_has_side_effects(AST_Block, function(compressor) {
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return any(this.body, compressor);
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});
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def_has_side_effects(AST_Call, function(compressor) {
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if (
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!this.is_callee_pure(compressor)
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&& (!this.expression.is_call_pure(compressor)
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|| this.expression.has_side_effects(compressor))
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) {
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return true;
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}
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return any(this.args, compressor);
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});
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def_has_side_effects(AST_Switch, function(compressor) {
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return this.expression.has_side_effects(compressor)
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|| any(this.body, compressor);
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});
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def_has_side_effects(AST_Case, function(compressor) {
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return this.expression.has_side_effects(compressor)
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|| any(this.body, compressor);
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});
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def_has_side_effects(AST_Try, function(compressor) {
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return this.body.has_side_effects(compressor)
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|| this.bcatch && this.bcatch.has_side_effects(compressor)
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|| this.bfinally && this.bfinally.has_side_effects(compressor);
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});
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def_has_side_effects(AST_If, function(compressor) {
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return this.condition.has_side_effects(compressor)
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|| this.body && this.body.has_side_effects(compressor)
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|| this.alternative && this.alternative.has_side_effects(compressor);
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});
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def_has_side_effects(AST_ImportMeta, return_false);
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def_has_side_effects(AST_LabeledStatement, function(compressor) {
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return this.body.has_side_effects(compressor);
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});
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def_has_side_effects(AST_SimpleStatement, function(compressor) {
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return this.body.has_side_effects(compressor);
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});
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def_has_side_effects(AST_Lambda, return_false);
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def_has_side_effects(AST_Class, function (compressor) {
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if (this.extends && this.extends.has_side_effects(compressor)) {
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return true;
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}
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return any(this.properties, compressor);
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});
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def_has_side_effects(AST_ClassStaticBlock, function(compressor) {
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return any(this.body, compressor);
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});
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def_has_side_effects(AST_Binary, function(compressor) {
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return this.left.has_side_effects(compressor)
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|| this.right.has_side_effects(compressor);
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});
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def_has_side_effects(AST_Assign, return_true);
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def_has_side_effects(AST_Conditional, function(compressor) {
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return this.condition.has_side_effects(compressor)
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|| this.consequent.has_side_effects(compressor)
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|| this.alternative.has_side_effects(compressor);
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});
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def_has_side_effects(AST_Unary, function(compressor) {
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return unary_side_effects.has(this.operator)
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|| this.expression.has_side_effects(compressor);
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});
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def_has_side_effects(AST_SymbolRef, function(compressor) {
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return !this.is_declared(compressor) && !pure_prop_access_globals.has(this.name);
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});
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def_has_side_effects(AST_SymbolClassProperty, return_false);
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def_has_side_effects(AST_SymbolDeclaration, return_false);
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def_has_side_effects(AST_Object, function(compressor) {
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return any(this.properties, compressor);
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});
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def_has_side_effects(AST_ObjectProperty, function(compressor) {
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return (
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this.computed_key() && this.key.has_side_effects(compressor)
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|| this.value && this.value.has_side_effects(compressor)
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);
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});
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def_has_side_effects(AST_ClassProperty, function(compressor) {
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return (
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this.computed_key() && this.key.has_side_effects(compressor)
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|| this.static && this.value && this.value.has_side_effects(compressor)
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);
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});
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def_has_side_effects(AST_ConciseMethod, function(compressor) {
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return this.computed_key() && this.key.has_side_effects(compressor);
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});
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def_has_side_effects(AST_ObjectGetter, function(compressor) {
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return this.computed_key() && this.key.has_side_effects(compressor);
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});
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def_has_side_effects(AST_ObjectSetter, function(compressor) {
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return this.computed_key() && this.key.has_side_effects(compressor);
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});
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def_has_side_effects(AST_Array, function(compressor) {
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return any(this.elements, compressor);
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});
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def_has_side_effects(AST_Dot, function(compressor) {
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if (is_nullish(this, compressor)) {
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return this.expression.has_side_effects(compressor);
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}
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if (!this.optional && this.expression.may_throw_on_access(compressor)) {
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return true;
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}
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return this.expression.has_side_effects(compressor);
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});
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def_has_side_effects(AST_Sub, function(compressor) {
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if (is_nullish(this, compressor)) {
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return this.expression.has_side_effects(compressor);
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}
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if (!this.optional && this.expression.may_throw_on_access(compressor)) {
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return true;
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}
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var property = this.property.has_side_effects(compressor);
|
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if (property && this.optional) return true; // "?." is a condition
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return property || this.expression.has_side_effects(compressor);
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});
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def_has_side_effects(AST_Chain, function (compressor) {
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return this.expression.has_side_effects(compressor);
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});
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def_has_side_effects(AST_Sequence, function(compressor) {
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return any(this.expressions, compressor);
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});
|
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def_has_side_effects(AST_Definitions, function(compressor) {
|
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return any(this.definitions, compressor);
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});
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def_has_side_effects(AST_VarDef, function() {
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return this.value != null;
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});
|
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def_has_side_effects(AST_TemplateSegment, return_false);
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def_has_side_effects(AST_TemplateString, function(compressor) {
|
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return any(this.segments, compressor);
|
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});
|
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})(function(node, func) {
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node.DEFMETHOD("has_side_effects", func);
|
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});
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|
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// determine if expression may throw
|
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(function(def_may_throw) {
|
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def_may_throw(AST_Node, return_true);
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|
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def_may_throw(AST_Constant, return_false);
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def_may_throw(AST_EmptyStatement, return_false);
|
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def_may_throw(AST_Lambda, return_false);
|
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def_may_throw(AST_SymbolDeclaration, return_false);
|
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def_may_throw(AST_This, return_false);
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def_may_throw(AST_ImportMeta, return_false);
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function any(list, compressor) {
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for (var i = list.length; --i >= 0;)
|
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if (list[i].may_throw(compressor))
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return true;
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return false;
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}
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|
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def_may_throw(AST_Class, function(compressor) {
|
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if (this.extends && this.extends.may_throw(compressor)) return true;
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return any(this.properties, compressor);
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});
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def_may_throw(AST_ClassStaticBlock, function (compressor) {
|
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return any(this.body, compressor);
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});
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|
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def_may_throw(AST_Array, function(compressor) {
|
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return any(this.elements, compressor);
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});
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def_may_throw(AST_Assign, function(compressor) {
|
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if (this.right.may_throw(compressor)) return true;
|
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if (!compressor.has_directive("use strict")
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&& this.operator == "="
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&& this.left instanceof AST_SymbolRef) {
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return false;
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}
|
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return this.left.may_throw(compressor);
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});
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def_may_throw(AST_Binary, function(compressor) {
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return this.left.may_throw(compressor)
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|| this.right.may_throw(compressor);
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});
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def_may_throw(AST_Block, function(compressor) {
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return any(this.body, compressor);
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|
});
|
|
def_may_throw(AST_Call, function(compressor) {
|
|
if (is_nullish(this, compressor)) return false;
|
|
if (any(this.args, compressor)) return true;
|
|
if (this.is_callee_pure(compressor)) return false;
|
|
if (this.expression.may_throw(compressor)) return true;
|
|
return !(this.expression instanceof AST_Lambda)
|
|
|| any(this.expression.body, compressor);
|
|
});
|
|
def_may_throw(AST_Case, function(compressor) {
|
|
return this.expression.may_throw(compressor)
|
|
|| any(this.body, compressor);
|
|
});
|
|
def_may_throw(AST_Conditional, function(compressor) {
|
|
return this.condition.may_throw(compressor)
|
|
|| this.consequent.may_throw(compressor)
|
|
|| this.alternative.may_throw(compressor);
|
|
});
|
|
def_may_throw(AST_Definitions, function(compressor) {
|
|
return any(this.definitions, compressor);
|
|
});
|
|
def_may_throw(AST_If, function(compressor) {
|
|
return this.condition.may_throw(compressor)
|
|
|| this.body && this.body.may_throw(compressor)
|
|
|| this.alternative && this.alternative.may_throw(compressor);
|
|
});
|
|
def_may_throw(AST_LabeledStatement, function(compressor) {
|
|
return this.body.may_throw(compressor);
|
|
});
|
|
def_may_throw(AST_Object, function(compressor) {
|
|
return any(this.properties, compressor);
|
|
});
|
|
def_may_throw(AST_ObjectProperty, function(compressor) {
|
|
// TODO key may throw too
|
|
return this.value ? this.value.may_throw(compressor) : false;
|
|
});
|
|
def_may_throw(AST_ClassProperty, function(compressor) {
|
|
return (
|
|
this.computed_key() && this.key.may_throw(compressor)
|
|
|| this.static && this.value && this.value.may_throw(compressor)
|
|
);
|
|
});
|
|
def_may_throw(AST_ConciseMethod, function(compressor) {
|
|
return this.computed_key() && this.key.may_throw(compressor);
|
|
});
|
|
def_may_throw(AST_ObjectGetter, function(compressor) {
|
|
return this.computed_key() && this.key.may_throw(compressor);
|
|
});
|
|
def_may_throw(AST_ObjectSetter, function(compressor) {
|
|
return this.computed_key() && this.key.may_throw(compressor);
|
|
});
|
|
def_may_throw(AST_Return, function(compressor) {
|
|
return this.value && this.value.may_throw(compressor);
|
|
});
|
|
def_may_throw(AST_Sequence, function(compressor) {
|
|
return any(this.expressions, compressor);
|
|
});
|
|
def_may_throw(AST_SimpleStatement, function(compressor) {
|
|
return this.body.may_throw(compressor);
|
|
});
|
|
def_may_throw(AST_Dot, function(compressor) {
|
|
if (is_nullish(this, compressor)) return false;
|
|
return !this.optional && this.expression.may_throw_on_access(compressor)
|
|
|| this.expression.may_throw(compressor);
|
|
});
|
|
def_may_throw(AST_Sub, function(compressor) {
|
|
if (is_nullish(this, compressor)) return false;
|
|
return !this.optional && this.expression.may_throw_on_access(compressor)
|
|
|| this.expression.may_throw(compressor)
|
|
|| this.property.may_throw(compressor);
|
|
});
|
|
def_may_throw(AST_Chain, function(compressor) {
|
|
return this.expression.may_throw(compressor);
|
|
});
|
|
def_may_throw(AST_Switch, function(compressor) {
|
|
return this.expression.may_throw(compressor)
|
|
|| any(this.body, compressor);
|
|
});
|
|
def_may_throw(AST_SymbolRef, function(compressor) {
|
|
return !this.is_declared(compressor) && !pure_prop_access_globals.has(this.name);
|
|
});
|
|
def_may_throw(AST_SymbolClassProperty, return_false);
|
|
def_may_throw(AST_Try, function(compressor) {
|
|
return this.bcatch ? this.bcatch.may_throw(compressor) : this.body.may_throw(compressor)
|
|
|| this.bfinally && this.bfinally.may_throw(compressor);
|
|
});
|
|
def_may_throw(AST_Unary, function(compressor) {
|
|
if (this.operator == "typeof" && this.expression instanceof AST_SymbolRef)
|
|
return false;
|
|
return this.expression.may_throw(compressor);
|
|
});
|
|
def_may_throw(AST_VarDef, function(compressor) {
|
|
if (!this.value) return false;
|
|
return this.value.may_throw(compressor);
|
|
});
|
|
})(function(node, func) {
|
|
node.DEFMETHOD("may_throw", func);
|
|
});
|
|
|
|
// determine if expression is constant
|
|
(function(def_is_constant_expression) {
|
|
function all_refs_local(scope) {
|
|
let result = true;
|
|
walk(this, node => {
|
|
if (node instanceof AST_SymbolRef) {
|
|
if (has_flag(this, INLINED)) {
|
|
result = false;
|
|
return walk_abort;
|
|
}
|
|
var def = node.definition();
|
|
if (
|
|
member(def, this.enclosed)
|
|
&& !this.variables.has(def.name)
|
|
) {
|
|
if (scope) {
|
|
var scope_def = scope.find_variable(node);
|
|
if (def.undeclared ? !scope_def : scope_def === def) {
|
|
result = "f";
|
|
return true;
|
|
}
|
|
}
|
|
result = false;
|
|
return walk_abort;
|
|
}
|
|
return true;
|
|
}
|
|
if (node instanceof AST_This && this instanceof AST_Arrow) {
|
|
result = false;
|
|
return walk_abort;
|
|
}
|
|
});
|
|
return result;
|
|
}
|
|
|
|
def_is_constant_expression(AST_Node, return_false);
|
|
def_is_constant_expression(AST_Constant, return_true);
|
|
def_is_constant_expression(AST_Class, function(scope) {
|
|
if (this.extends && !this.extends.is_constant_expression(scope)) {
|
|
return false;
|
|
}
|
|
|
|
for (const prop of this.properties) {
|
|
if (prop.computed_key() && !prop.key.is_constant_expression(scope)) {
|
|
return false;
|
|
}
|
|
if (prop.static && prop.value && !prop.value.is_constant_expression(scope)) {
|
|
return false;
|
|
}
|
|
if (prop instanceof AST_ClassStaticBlock) {
|
|
return false;
|
|
}
|
|
}
|
|
|
|
return all_refs_local.call(this, scope);
|
|
});
|
|
def_is_constant_expression(AST_Lambda, all_refs_local);
|
|
def_is_constant_expression(AST_Unary, function() {
|
|
return this.expression.is_constant_expression();
|
|
});
|
|
def_is_constant_expression(AST_Binary, function() {
|
|
return this.left.is_constant_expression()
|
|
&& this.right.is_constant_expression();
|
|
});
|
|
def_is_constant_expression(AST_Array, function() {
|
|
return this.elements.every((l) => l.is_constant_expression());
|
|
});
|
|
def_is_constant_expression(AST_Object, function() {
|
|
return this.properties.every((l) => l.is_constant_expression());
|
|
});
|
|
def_is_constant_expression(AST_ObjectProperty, function() {
|
|
return !!(!(this.key instanceof AST_Node) && this.value && this.value.is_constant_expression());
|
|
});
|
|
})(function(node, func) {
|
|
node.DEFMETHOD("is_constant_expression", func);
|
|
});
|
|
|
|
|
|
// may_throw_on_access()
|
|
// returns true if this node may be null, undefined or contain `AST_Accessor`
|
|
(function(def_may_throw_on_access) {
|
|
AST_Node.DEFMETHOD("may_throw_on_access", function(compressor) {
|
|
return !compressor.option("pure_getters")
|
|
|| this._dot_throw(compressor);
|
|
});
|
|
|
|
function is_strict(compressor) {
|
|
return /strict/.test(compressor.option("pure_getters"));
|
|
}
|
|
|
|
def_may_throw_on_access(AST_Node, is_strict);
|
|
def_may_throw_on_access(AST_Null, return_true);
|
|
def_may_throw_on_access(AST_Undefined, return_true);
|
|
def_may_throw_on_access(AST_Constant, return_false);
|
|
def_may_throw_on_access(AST_Array, return_false);
|
|
def_may_throw_on_access(AST_Object, function(compressor) {
|
|
if (!is_strict(compressor)) return false;
|
|
for (var i = this.properties.length; --i >=0;)
|
|
if (this.properties[i]._dot_throw(compressor)) return true;
|
|
return false;
|
|
});
|
|
// Do not be as strict with classes as we are with objects.
|
|
// Hopefully the community is not going to abuse static getters and setters.
|
|
// https://github.com/terser/terser/issues/724#issuecomment-643655656
|
|
def_may_throw_on_access(AST_Class, return_false);
|
|
def_may_throw_on_access(AST_ObjectProperty, return_false);
|
|
def_may_throw_on_access(AST_ObjectGetter, return_true);
|
|
def_may_throw_on_access(AST_Expansion, function(compressor) {
|
|
return this.expression._dot_throw(compressor);
|
|
});
|
|
def_may_throw_on_access(AST_Function, return_false);
|
|
def_may_throw_on_access(AST_Arrow, return_false);
|
|
def_may_throw_on_access(AST_UnaryPostfix, return_false);
|
|
def_may_throw_on_access(AST_UnaryPrefix, function() {
|
|
return this.operator == "void";
|
|
});
|
|
def_may_throw_on_access(AST_Binary, function(compressor) {
|
|
return (this.operator == "&&" || this.operator == "||" || this.operator == "??")
|
|
&& (this.left._dot_throw(compressor) || this.right._dot_throw(compressor));
|
|
});
|
|
def_may_throw_on_access(AST_Assign, function(compressor) {
|
|
if (this.logical) return true;
|
|
|
|
return this.operator == "="
|
|
&& this.right._dot_throw(compressor);
|
|
});
|
|
def_may_throw_on_access(AST_Conditional, function(compressor) {
|
|
return this.consequent._dot_throw(compressor)
|
|
|| this.alternative._dot_throw(compressor);
|
|
});
|
|
def_may_throw_on_access(AST_Dot, function(compressor) {
|
|
if (!is_strict(compressor)) return false;
|
|
|
|
if (this.property == "prototype") {
|
|
return !(
|
|
this.expression instanceof AST_Function
|
|
|| this.expression instanceof AST_Class
|
|
);
|
|
}
|
|
return true;
|
|
});
|
|
def_may_throw_on_access(AST_Chain, function(compressor) {
|
|
return this.expression._dot_throw(compressor);
|
|
});
|
|
def_may_throw_on_access(AST_Sequence, function(compressor) {
|
|
return this.tail_node()._dot_throw(compressor);
|
|
});
|
|
def_may_throw_on_access(AST_SymbolRef, function(compressor) {
|
|
if (this.name === "arguments" && this.scope instanceof AST_Lambda) return false;
|
|
if (has_flag(this, UNDEFINED)) return true;
|
|
if (!is_strict(compressor)) return false;
|
|
if (is_undeclared_ref(this) && this.is_declared(compressor)) return false;
|
|
if (this.is_immutable()) return false;
|
|
var fixed = this.fixed_value();
|
|
return !fixed || fixed._dot_throw(compressor);
|
|
});
|
|
})(function(node, func) {
|
|
node.DEFMETHOD("_dot_throw", func);
|
|
});
|
|
|
|
export function is_lhs(node, parent) {
|
|
if (parent instanceof AST_Unary && unary_side_effects.has(parent.operator)) return parent.expression;
|
|
if (parent instanceof AST_Assign && parent.left === node) return node;
|
|
if (parent instanceof AST_ForIn && parent.init === node) return node;
|
|
}
|
|
|
|
// method to negate an expression
|
|
(function(def_negate) {
|
|
function basic_negation(exp) {
|
|
return make_node(AST_UnaryPrefix, exp, {
|
|
operator: "!",
|
|
expression: exp
|
|
});
|
|
}
|
|
function best(orig, alt, first_in_statement) {
|
|
var negated = basic_negation(orig);
|
|
if (first_in_statement) {
|
|
var stat = make_node(AST_SimpleStatement, alt, {
|
|
body: alt
|
|
});
|
|
return best_of_expression(negated, stat) === stat ? alt : negated;
|
|
}
|
|
return best_of_expression(negated, alt);
|
|
}
|
|
def_negate(AST_Node, function() {
|
|
return basic_negation(this);
|
|
});
|
|
def_negate(AST_Statement, function() {
|
|
throw new Error("Cannot negate a statement");
|
|
});
|
|
def_negate(AST_Function, function() {
|
|
return basic_negation(this);
|
|
});
|
|
def_negate(AST_Class, function() {
|
|
return basic_negation(this);
|
|
});
|
|
def_negate(AST_Arrow, function() {
|
|
return basic_negation(this);
|
|
});
|
|
def_negate(AST_UnaryPrefix, function() {
|
|
if (this.operator == "!")
|
|
return this.expression;
|
|
return basic_negation(this);
|
|
});
|
|
def_negate(AST_Sequence, function(compressor) {
|
|
var expressions = this.expressions.slice();
|
|
expressions.push(expressions.pop().negate(compressor));
|
|
return make_sequence(this, expressions);
|
|
});
|
|
def_negate(AST_Conditional, function(compressor, first_in_statement) {
|
|
var self = this.clone();
|
|
self.consequent = self.consequent.negate(compressor);
|
|
self.alternative = self.alternative.negate(compressor);
|
|
return best(this, self, first_in_statement);
|
|
});
|
|
def_negate(AST_Binary, function(compressor, first_in_statement) {
|
|
var self = this.clone(), op = this.operator;
|
|
if (compressor.option("unsafe_comps")) {
|
|
switch (op) {
|
|
case "<=" : self.operator = ">" ; return self;
|
|
case "<" : self.operator = ">=" ; return self;
|
|
case ">=" : self.operator = "<" ; return self;
|
|
case ">" : self.operator = "<=" ; return self;
|
|
}
|
|
}
|
|
switch (op) {
|
|
case "==" : self.operator = "!="; return self;
|
|
case "!=" : self.operator = "=="; return self;
|
|
case "===": self.operator = "!=="; return self;
|
|
case "!==": self.operator = "==="; return self;
|
|
case "&&":
|
|
self.operator = "||";
|
|
self.left = self.left.negate(compressor, first_in_statement);
|
|
self.right = self.right.negate(compressor);
|
|
return best(this, self, first_in_statement);
|
|
case "||":
|
|
self.operator = "&&";
|
|
self.left = self.left.negate(compressor, first_in_statement);
|
|
self.right = self.right.negate(compressor);
|
|
return best(this, self, first_in_statement);
|
|
}
|
|
return basic_negation(this);
|
|
});
|
|
})(function(node, func) {
|
|
node.DEFMETHOD("negate", function(compressor, first_in_statement) {
|
|
return func.call(this, compressor, first_in_statement);
|
|
});
|
|
});
|
|
|
|
(function (def_bitwise_negate) {
|
|
function basic_negation(exp) {
|
|
return make_node(AST_UnaryPrefix, exp, {
|
|
operator: "~",
|
|
expression: exp
|
|
});
|
|
}
|
|
|
|
def_bitwise_negate(AST_Node, function() {
|
|
return basic_negation(this);
|
|
});
|
|
|
|
def_bitwise_negate(AST_Number, function() {
|
|
const neg = ~this.value;
|
|
if (neg.toString().length > this.value.toString().length) {
|
|
return basic_negation(this);
|
|
}
|
|
return make_node(AST_Number, this, { value: neg });
|
|
});
|
|
|
|
def_bitwise_negate(AST_UnaryPrefix, function(in_32_bit_context) {
|
|
if (this.operator == "~" && (in_32_bit_context || this.expression.is_32_bit_integer())) {
|
|
return this.expression;
|
|
} else {
|
|
return basic_negation(this);
|
|
}
|
|
});
|
|
})(function (node, func) {
|
|
node.DEFMETHOD("bitwise_negate", func);
|
|
});
|
|
|
|
// Is the callee of this function pure?
|
|
var global_pure_fns = makePredicate("Boolean decodeURI decodeURIComponent Date encodeURI encodeURIComponent Error escape EvalError isFinite isNaN Number Object parseFloat parseInt RangeError ReferenceError String SyntaxError TypeError unescape URIError");
|
|
AST_Call.DEFMETHOD("is_callee_pure", function(compressor) {
|
|
if (compressor.option("unsafe")) {
|
|
var expr = this.expression;
|
|
var first_arg = (this.args && this.args[0] && this.args[0].evaluate(compressor));
|
|
if (
|
|
expr.expression && expr.expression.name === "hasOwnProperty" &&
|
|
(first_arg == null || first_arg.thedef && first_arg.thedef.undeclared)
|
|
) {
|
|
return false;
|
|
}
|
|
if (is_undeclared_ref(expr) && global_pure_fns.has(expr.name)) return true;
|
|
if (
|
|
expr instanceof AST_Dot
|
|
&& is_undeclared_ref(expr.expression)
|
|
&& is_pure_native_fn(expr.expression.name, expr.property)
|
|
) {
|
|
return true;
|
|
}
|
|
}
|
|
if ((this instanceof AST_New) && compressor.option("pure_new")) {
|
|
return true;
|
|
}
|
|
if (compressor.option("side_effects") && has_annotation(this, _PURE)) {
|
|
return true;
|
|
}
|
|
return !compressor.pure_funcs(this);
|
|
});
|
|
|
|
// If I call this, is it a pure function?
|
|
AST_Node.DEFMETHOD("is_call_pure", return_false);
|
|
AST_Dot.DEFMETHOD("is_call_pure", function(compressor) {
|
|
if (!compressor.option("unsafe")) return;
|
|
const expr = this.expression;
|
|
|
|
let native_obj;
|
|
if (expr instanceof AST_Array) {
|
|
native_obj = "Array";
|
|
} else if (expr.is_boolean()) {
|
|
native_obj = "Boolean";
|
|
} else if (expr.is_number(compressor)) {
|
|
native_obj = "Number";
|
|
} else if (expr instanceof AST_RegExp) {
|
|
native_obj = "RegExp";
|
|
} else if (expr.is_string(compressor)) {
|
|
native_obj = "String";
|
|
} else if (!this.may_throw_on_access(compressor)) {
|
|
native_obj = "Object";
|
|
}
|
|
return native_obj != null && is_pure_native_method(native_obj, this.property);
|
|
});
|
|
|
|
// tell me if a statement aborts
|
|
export const aborts = (thing) => thing && thing.aborts();
|
|
|
|
(function(def_aborts) {
|
|
def_aborts(AST_Statement, return_null);
|
|
def_aborts(AST_Jump, return_this);
|
|
function block_aborts() {
|
|
for (var i = 0; i < this.body.length; i++) {
|
|
if (aborts(this.body[i])) {
|
|
return this.body[i];
|
|
}
|
|
}
|
|
return null;
|
|
}
|
|
def_aborts(AST_Import, return_null);
|
|
def_aborts(AST_BlockStatement, block_aborts);
|
|
def_aborts(AST_SwitchBranch, block_aborts);
|
|
def_aborts(AST_DefClass, function () {
|
|
for (const prop of this.properties) {
|
|
if (prop instanceof AST_ClassStaticBlock) {
|
|
if (prop.aborts()) return prop;
|
|
}
|
|
}
|
|
return null;
|
|
});
|
|
def_aborts(AST_ClassStaticBlock, block_aborts);
|
|
def_aborts(AST_If, function() {
|
|
return this.alternative && aborts(this.body) && aborts(this.alternative) && this;
|
|
});
|
|
})(function(node, func) {
|
|
node.DEFMETHOD("aborts", func);
|
|
});
|
|
|
|
AST_Node.DEFMETHOD("contains_this", function() {
|
|
return walk(this, node => {
|
|
if (node instanceof AST_This) return walk_abort;
|
|
if (
|
|
node !== this
|
|
&& node instanceof AST_Scope
|
|
&& !(node instanceof AST_Arrow)
|
|
) {
|
|
return true;
|
|
}
|
|
});
|
|
});
|
|
|
|
export function is_modified(compressor, tw, node, value, level, immutable) {
|
|
var parent = tw.parent(level);
|
|
var lhs = is_lhs(node, parent);
|
|
if (lhs) return lhs;
|
|
if (!immutable
|
|
&& parent instanceof AST_Call
|
|
&& parent.expression === node
|
|
&& !(value instanceof AST_Arrow)
|
|
&& !(value instanceof AST_Class)
|
|
&& !parent.is_callee_pure(compressor)
|
|
&& (!(value instanceof AST_Function)
|
|
|| !(parent instanceof AST_New) && value.contains_this())) {
|
|
return true;
|
|
}
|
|
if (parent instanceof AST_Array) {
|
|
return is_modified(compressor, tw, parent, parent, level + 1);
|
|
}
|
|
if (parent instanceof AST_ObjectKeyVal && node === parent.value) {
|
|
var obj = tw.parent(level + 1);
|
|
return is_modified(compressor, tw, obj, obj, level + 2);
|
|
}
|
|
if (parent instanceof AST_PropAccess && parent.expression === node) {
|
|
var prop = read_property(value, parent.property);
|
|
return !immutable && is_modified(compressor, tw, parent, prop, level + 1);
|
|
}
|
|
}
|