231 lines
8.4 KiB
JavaScript
231 lines
8.4 KiB
JavaScript
|
/**
|
||
|
|
* @fileoverview Disallow reassignment of function parameters.
|
||
|
|
* @author Nat Burns
|
||
|
|
*/
|
||
|
|
"use strict";
|
||
|
|
|
||
|
|
//------------------------------------------------------------------------------
|
||
|
|
// Rule Definition
|
||
|
|
//------------------------------------------------------------------------------
|
||
|
|
|
||
|
|
const stopNodePattern = /(?:Statement|Declaration|Function(?:Expression)?|Program)$/u;
|
||
|
|
|
||
|
|
/** @type {import('../shared/types').Rule} */
|
||
|
|
module.exports = {
|
||
|
|
meta: {
|
||
|
|
type: "suggestion",
|
||
|
|
|
||
|
|
docs: {
|
||
|
|
description: "Disallow reassigning `function` parameters",
|
||
|
|
recommended: false,
|
||
|
|
url: "https://eslint.org/docs/latest/rules/no-param-reassign"
|
||
|
|
},
|
||
|
|
|
||
|
|
schema: [
|
||
|
|
{
|
||
|
|
oneOf: [
|
||
|
|
{
|
||
|
|
type: "object",
|
||
|
|
properties: {
|
||
|
|
props: {
|
||
|
|
enum: [false]
|
||
|
|
}
|
||
|
|
},
|
||
|
|
additionalProperties: false
|
||
|
|
},
|
||
|
|
{
|
||
|
|
type: "object",
|
||
|
|
properties: {
|
||
|
|
props: {
|
||
|
|
enum: [true]
|
||
|
|
},
|
||
|
|
ignorePropertyModificationsFor: {
|
||
|
|
type: "array",
|
||
|
|
items: {
|
||
|
|
type: "string"
|
||
|
|
},
|
||
|
|
uniqueItems: true
|
||
|
|
},
|
||
|
|
ignorePropertyModificationsForRegex: {
|
||
|
|
type: "array",
|
||
|
|
items: {
|
||
|
|
type: "string"
|
||
|
|
},
|
||
|
|
uniqueItems: true
|
||
|
|
}
|
||
|
|
},
|
||
|
|
additionalProperties: false
|
||
|
|
}
|
||
|
|
]
|
||
|
|
}
|
||
|
|
],
|
||
|
|
|
||
|
|
messages: {
|
||
|
|
assignmentToFunctionParam: "Assignment to function parameter '{{name}}'.",
|
||
|
|
assignmentToFunctionParamProp: "Assignment to property of function parameter '{{name}}'."
|
||
|
|
}
|
||
|
|
},
|
||
|
|
|
||
|
|
create(context) {
|
||
|
|
const props = context.options[0] && context.options[0].props;
|
||
|
|
const ignoredPropertyAssignmentsFor = context.options[0] && context.options[0].ignorePropertyModificationsFor || [];
|
||
|
|
const ignoredPropertyAssignmentsForRegex = context.options[0] && context.options[0].ignorePropertyModificationsForRegex || [];
|
||
|
|
const sourceCode = context.sourceCode;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Checks whether or not the reference modifies properties of its variable.
|
||
|
|
* @param {Reference} reference A reference to check.
|
||
|
|
* @returns {boolean} Whether or not the reference modifies properties of its variable.
|
||
|
|
*/
|
||
|
|
function isModifyingProp(reference) {
|
||
|
|
let node = reference.identifier;
|
||
|
|
let parent = node.parent;
|
||
|
|
|
||
|
|
while (parent && (!stopNodePattern.test(parent.type) ||
|
||
|
|
parent.type === "ForInStatement" || parent.type === "ForOfStatement")) {
|
||
|
|
switch (parent.type) {
|
||
|
|
|
||
|
|
// e.g. foo.a = 0;
|
||
|
|
case "AssignmentExpression":
|
||
|
|
return parent.left === node;
|
||
|
|
|
||
|
|
// e.g. ++foo.a;
|
||
|
|
case "UpdateExpression":
|
||
|
|
return true;
|
||
|
|
|
||
|
|
// e.g. delete foo.a;
|
||
|
|
case "UnaryExpression":
|
||
|
|
if (parent.operator === "delete") {
|
||
|
|
return true;
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
|
||
|
|
// e.g. for (foo.a in b) {}
|
||
|
|
case "ForInStatement":
|
||
|
|
case "ForOfStatement":
|
||
|
|
if (parent.left === node) {
|
||
|
|
return true;
|
||
|
|
}
|
||
|
|
|
||
|
|
// this is a stop node for parent.right and parent.body
|
||
|
|
return false;
|
||
|
|
|
||
|
|
// EXCLUDES: e.g. cache.get(foo.a).b = 0;
|
||
|
|
case "CallExpression":
|
||
|
|
if (parent.callee !== node) {
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
|
||
|
|
// EXCLUDES: e.g. cache[foo.a] = 0;
|
||
|
|
case "MemberExpression":
|
||
|
|
if (parent.property === node) {
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
|
||
|
|
// EXCLUDES: e.g. ({ [foo]: a }) = bar;
|
||
|
|
case "Property":
|
||
|
|
if (parent.key === node) {
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
|
||
|
|
break;
|
||
|
|
|
||
|
|
// EXCLUDES: e.g. (foo ? a : b).c = bar;
|
||
|
|
case "ConditionalExpression":
|
||
|
|
if (parent.test === node) {
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
|
||
|
|
break;
|
||
|
|
|
||
|
|
// no default
|
||
|
|
}
|
||
|
|
|
||
|
|
node = parent;
|
||
|
|
parent = node.parent;
|
||
|
|
}
|
||
|
|
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Tests that an identifier name matches any of the ignored property assignments.
|
||
|
|
* First we test strings in ignoredPropertyAssignmentsFor.
|
||
|
|
* Then we instantiate and test RegExp objects from ignoredPropertyAssignmentsForRegex strings.
|
||
|
|
* @param {string} identifierName A string that describes the name of an identifier to
|
||
|
|
* ignore property assignments for.
|
||
|
|
* @returns {boolean} Whether the string matches an ignored property assignment regular expression or not.
|
||
|
|
*/
|
||
|
|
function isIgnoredPropertyAssignment(identifierName) {
|
||
|
|
return ignoredPropertyAssignmentsFor.includes(identifierName) ||
|
||
|
|
ignoredPropertyAssignmentsForRegex.some(ignored => new RegExp(ignored, "u").test(identifierName));
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Reports a reference if is non initializer and writable.
|
||
|
|
* @param {Reference} reference A reference to check.
|
||
|
|
* @param {int} index The index of the reference in the references.
|
||
|
|
* @param {Reference[]} references The array that the reference belongs to.
|
||
|
|
* @returns {void}
|
||
|
|
*/
|
||
|
|
function checkReference(reference, index, references) {
|
||
|
|
const identifier = reference.identifier;
|
||
|
|
|
||
|
|
if (identifier &&
|
||
|
|
!reference.init &&
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Destructuring assignments can have multiple default value,
|
||
|
|
* so possibly there are multiple writeable references for the same identifier.
|
||
|
|
*/
|
||
|
|
(index === 0 || references[index - 1].identifier !== identifier)
|
||
|
|
) {
|
||
|
|
if (reference.isWrite()) {
|
||
|
|
context.report({
|
||
|
|
node: identifier,
|
||
|
|
messageId: "assignmentToFunctionParam",
|
||
|
|
data: { name: identifier.name }
|
||
|
|
});
|
||
|
|
} else if (props && isModifyingProp(reference) && !isIgnoredPropertyAssignment(identifier.name)) {
|
||
|
|
context.report({
|
||
|
|
node: identifier,
|
||
|
|
messageId: "assignmentToFunctionParamProp",
|
||
|
|
data: { name: identifier.name }
|
||
|
|
});
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Finds and reports references that are non initializer and writable.
|
||
|
|
* @param {Variable} variable A variable to check.
|
||
|
|
* @returns {void}
|
||
|
|
*/
|
||
|
|
function checkVariable(variable) {
|
||
|
|
if (variable.defs[0].type === "Parameter") {
|
||
|
|
variable.references.forEach(checkReference);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Checks parameters of a given function node.
|
||
|
|
* @param {ASTNode} node A function node to check.
|
||
|
|
* @returns {void}
|
||
|
|
*/
|
||
|
|
function checkForFunction(node) {
|
||
|
|
sourceCode.getDeclaredVariables(node).forEach(checkVariable);
|
||
|
|
}
|
||
|
|
|
||
|
|
return {
|
||
|
|
|
||
|
|
// `:exit` is needed for the `node.parent` property of identifier nodes.
|
||
|
|
"FunctionDeclaration:exit": checkForFunction,
|
||
|
|
"FunctionExpression:exit": checkForFunction,
|
||
|
|
"ArrowFunctionExpression:exit": checkForFunction
|
||
|
|
};
|
||
|
|
|
||
|
|
}
|
||
|
|
};
|