297 lines
13 KiB
JavaScript
297 lines
13 KiB
JavaScript
|
/**
|
||
|
|
* @fileoverview Rule to require braces in arrow function body.
|
||
|
|
* @author Alberto Rodríguez
|
||
|
|
*/
|
||
|
|
"use strict";
|
||
|
|
|
||
|
|
//------------------------------------------------------------------------------
|
||
|
|
// Requirements
|
||
|
|
//------------------------------------------------------------------------------
|
||
|
|
|
||
|
|
const astUtils = require("./utils/ast-utils");
|
||
|
|
|
||
|
|
//------------------------------------------------------------------------------
|
||
|
|
// Rule Definition
|
||
|
|
//------------------------------------------------------------------------------
|
||
|
|
|
||
|
|
/** @type {import('../shared/types').Rule} */
|
||
|
|
module.exports = {
|
||
|
|
meta: {
|
||
|
|
type: "suggestion",
|
||
|
|
|
||
|
|
docs: {
|
||
|
|
description: "Require braces around arrow function bodies",
|
||
|
|
recommended: false,
|
||
|
|
url: "https://eslint.org/docs/latest/rules/arrow-body-style"
|
||
|
|
},
|
||
|
|
|
||
|
|
schema: {
|
||
|
|
anyOf: [
|
||
|
|
{
|
||
|
|
type: "array",
|
||
|
|
items: [
|
||
|
|
{
|
||
|
|
enum: ["always", "never"]
|
||
|
|
}
|
||
|
|
],
|
||
|
|
minItems: 0,
|
||
|
|
maxItems: 1
|
||
|
|
},
|
||
|
|
{
|
||
|
|
type: "array",
|
||
|
|
items: [
|
||
|
|
{
|
||
|
|
enum: ["as-needed"]
|
||
|
|
},
|
||
|
|
{
|
||
|
|
type: "object",
|
||
|
|
properties: {
|
||
|
|
requireReturnForObjectLiteral: { type: "boolean" }
|
||
|
|
},
|
||
|
|
additionalProperties: false
|
||
|
|
}
|
||
|
|
],
|
||
|
|
minItems: 0,
|
||
|
|
maxItems: 2
|
||
|
|
}
|
||
|
|
]
|
||
|
|
},
|
||
|
|
|
||
|
|
fixable: "code",
|
||
|
|
|
||
|
|
messages: {
|
||
|
|
unexpectedOtherBlock: "Unexpected block statement surrounding arrow body.",
|
||
|
|
unexpectedEmptyBlock: "Unexpected block statement surrounding arrow body; put a value of `undefined` immediately after the `=>`.",
|
||
|
|
unexpectedObjectBlock: "Unexpected block statement surrounding arrow body; parenthesize the returned value and move it immediately after the `=>`.",
|
||
|
|
unexpectedSingleBlock: "Unexpected block statement surrounding arrow body; move the returned value immediately after the `=>`.",
|
||
|
|
expectedBlock: "Expected block statement surrounding arrow body."
|
||
|
|
}
|
||
|
|
},
|
||
|
|
|
||
|
|
create(context) {
|
||
|
|
const options = context.options;
|
||
|
|
const always = options[0] === "always";
|
||
|
|
const asNeeded = !options[0] || options[0] === "as-needed";
|
||
|
|
const never = options[0] === "never";
|
||
|
|
const requireReturnForObjectLiteral = options[1] && options[1].requireReturnForObjectLiteral;
|
||
|
|
const sourceCode = context.sourceCode;
|
||
|
|
let funcInfo = null;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Checks whether the given node has ASI problem or not.
|
||
|
|
* @param {Token} token The token to check.
|
||
|
|
* @returns {boolean} `true` if it changes semantics if `;` or `}` followed by the token are removed.
|
||
|
|
*/
|
||
|
|
function hasASIProblem(token) {
|
||
|
|
return token && token.type === "Punctuator" && /^[([/`+-]/u.test(token.value);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Gets the closing parenthesis by the given node.
|
||
|
|
* @param {ASTNode} node first node after an opening parenthesis.
|
||
|
|
* @returns {Token} The found closing parenthesis token.
|
||
|
|
*/
|
||
|
|
function findClosingParen(node) {
|
||
|
|
let nodeToCheck = node;
|
||
|
|
|
||
|
|
while (!astUtils.isParenthesised(sourceCode, nodeToCheck)) {
|
||
|
|
nodeToCheck = nodeToCheck.parent;
|
||
|
|
}
|
||
|
|
return sourceCode.getTokenAfter(nodeToCheck);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Check whether the node is inside of a for loop's init
|
||
|
|
* @param {ASTNode} node node is inside for loop
|
||
|
|
* @returns {boolean} `true` if the node is inside of a for loop, else `false`
|
||
|
|
*/
|
||
|
|
function isInsideForLoopInitializer(node) {
|
||
|
|
if (node && node.parent) {
|
||
|
|
if (node.parent.type === "ForStatement" && node.parent.init === node) {
|
||
|
|
return true;
|
||
|
|
}
|
||
|
|
return isInsideForLoopInitializer(node.parent);
|
||
|
|
}
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Determines whether a arrow function body needs braces
|
||
|
|
* @param {ASTNode} node The arrow function node.
|
||
|
|
* @returns {void}
|
||
|
|
*/
|
||
|
|
function validate(node) {
|
||
|
|
const arrowBody = node.body;
|
||
|
|
|
||
|
|
if (arrowBody.type === "BlockStatement") {
|
||
|
|
const blockBody = arrowBody.body;
|
||
|
|
|
||
|
|
if (blockBody.length !== 1 && !never) {
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (asNeeded && requireReturnForObjectLiteral && blockBody[0].type === "ReturnStatement" &&
|
||
|
|
blockBody[0].argument && blockBody[0].argument.type === "ObjectExpression") {
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (never || asNeeded && blockBody[0].type === "ReturnStatement") {
|
||
|
|
let messageId;
|
||
|
|
|
||
|
|
if (blockBody.length === 0) {
|
||
|
|
messageId = "unexpectedEmptyBlock";
|
||
|
|
} else if (blockBody.length > 1) {
|
||
|
|
messageId = "unexpectedOtherBlock";
|
||
|
|
} else if (blockBody[0].argument === null) {
|
||
|
|
messageId = "unexpectedSingleBlock";
|
||
|
|
} else if (astUtils.isOpeningBraceToken(sourceCode.getFirstToken(blockBody[0], { skip: 1 }))) {
|
||
|
|
messageId = "unexpectedObjectBlock";
|
||
|
|
} else {
|
||
|
|
messageId = "unexpectedSingleBlock";
|
||
|
|
}
|
||
|
|
|
||
|
|
context.report({
|
||
|
|
node,
|
||
|
|
loc: arrowBody.loc,
|
||
|
|
messageId,
|
||
|
|
fix(fixer) {
|
||
|
|
const fixes = [];
|
||
|
|
|
||
|
|
if (blockBody.length !== 1 ||
|
||
|
|
blockBody[0].type !== "ReturnStatement" ||
|
||
|
|
!blockBody[0].argument ||
|
||
|
|
hasASIProblem(sourceCode.getTokenAfter(arrowBody))
|
||
|
|
) {
|
||
|
|
return fixes;
|
||
|
|
}
|
||
|
|
|
||
|
|
const openingBrace = sourceCode.getFirstToken(arrowBody);
|
||
|
|
const closingBrace = sourceCode.getLastToken(arrowBody);
|
||
|
|
const firstValueToken = sourceCode.getFirstToken(blockBody[0], 1);
|
||
|
|
const lastValueToken = sourceCode.getLastToken(blockBody[0]);
|
||
|
|
const commentsExist =
|
||
|
|
sourceCode.commentsExistBetween(openingBrace, firstValueToken) ||
|
||
|
|
sourceCode.commentsExistBetween(lastValueToken, closingBrace);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Remove tokens around the return value.
|
||
|
|
* If comments don't exist, remove extra spaces as well.
|
||
|
|
*/
|
||
|
|
if (commentsExist) {
|
||
|
|
fixes.push(
|
||
|
|
fixer.remove(openingBrace),
|
||
|
|
fixer.remove(closingBrace),
|
||
|
|
fixer.remove(sourceCode.getTokenAfter(openingBrace)) // return keyword
|
||
|
|
);
|
||
|
|
} else {
|
||
|
|
fixes.push(
|
||
|
|
fixer.removeRange([openingBrace.range[0], firstValueToken.range[0]]),
|
||
|
|
fixer.removeRange([lastValueToken.range[1], closingBrace.range[1]])
|
||
|
|
);
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* If the first token of the return value is `{` or the return value is a sequence expression,
|
||
|
|
* enclose the return value by parentheses to avoid syntax error.
|
||
|
|
*/
|
||
|
|
if (astUtils.isOpeningBraceToken(firstValueToken) || blockBody[0].argument.type === "SequenceExpression" || (funcInfo.hasInOperator && isInsideForLoopInitializer(node))) {
|
||
|
|
if (!astUtils.isParenthesised(sourceCode, blockBody[0].argument)) {
|
||
|
|
fixes.push(
|
||
|
|
fixer.insertTextBefore(firstValueToken, "("),
|
||
|
|
fixer.insertTextAfter(lastValueToken, ")")
|
||
|
|
);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* If the last token of the return statement is semicolon, remove it.
|
||
|
|
* Non-block arrow body is an expression, not a statement.
|
||
|
|
*/
|
||
|
|
if (astUtils.isSemicolonToken(lastValueToken)) {
|
||
|
|
fixes.push(fixer.remove(lastValueToken));
|
||
|
|
}
|
||
|
|
|
||
|
|
return fixes;
|
||
|
|
}
|
||
|
|
});
|
||
|
|
}
|
||
|
|
} else {
|
||
|
|
if (always || (asNeeded && requireReturnForObjectLiteral && arrowBody.type === "ObjectExpression")) {
|
||
|
|
context.report({
|
||
|
|
node,
|
||
|
|
loc: arrowBody.loc,
|
||
|
|
messageId: "expectedBlock",
|
||
|
|
fix(fixer) {
|
||
|
|
const fixes = [];
|
||
|
|
const arrowToken = sourceCode.getTokenBefore(arrowBody, astUtils.isArrowToken);
|
||
|
|
const [firstTokenAfterArrow, secondTokenAfterArrow] = sourceCode.getTokensAfter(arrowToken, { count: 2 });
|
||
|
|
const lastToken = sourceCode.getLastToken(node);
|
||
|
|
|
||
|
|
let parenthesisedObjectLiteral = null;
|
||
|
|
|
||
|
|
if (
|
||
|
|
astUtils.isOpeningParenToken(firstTokenAfterArrow) &&
|
||
|
|
astUtils.isOpeningBraceToken(secondTokenAfterArrow)
|
||
|
|
) {
|
||
|
|
const braceNode = sourceCode.getNodeByRangeIndex(secondTokenAfterArrow.range[0]);
|
||
|
|
|
||
|
|
if (braceNode.type === "ObjectExpression") {
|
||
|
|
parenthesisedObjectLiteral = braceNode;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// If the value is object literal, remove parentheses which were forced by syntax.
|
||
|
|
if (parenthesisedObjectLiteral) {
|
||
|
|
const openingParenToken = firstTokenAfterArrow;
|
||
|
|
const openingBraceToken = secondTokenAfterArrow;
|
||
|
|
|
||
|
|
if (astUtils.isTokenOnSameLine(openingParenToken, openingBraceToken)) {
|
||
|
|
fixes.push(fixer.replaceText(openingParenToken, "{return "));
|
||
|
|
} else {
|
||
|
|
|
||
|
|
// Avoid ASI
|
||
|
|
fixes.push(
|
||
|
|
fixer.replaceText(openingParenToken, "{"),
|
||
|
|
fixer.insertTextBefore(openingBraceToken, "return ")
|
||
|
|
);
|
||
|
|
}
|
||
|
|
|
||
|
|
// Closing paren for the object doesn't have to be lastToken, e.g.: () => ({}).foo()
|
||
|
|
fixes.push(fixer.remove(findClosingParen(parenthesisedObjectLiteral)));
|
||
|
|
fixes.push(fixer.insertTextAfter(lastToken, "}"));
|
||
|
|
|
||
|
|
} else {
|
||
|
|
fixes.push(fixer.insertTextBefore(firstTokenAfterArrow, "{return "));
|
||
|
|
fixes.push(fixer.insertTextAfter(lastToken, "}"));
|
||
|
|
}
|
||
|
|
|
||
|
|
return fixes;
|
||
|
|
}
|
||
|
|
});
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
return {
|
||
|
|
"BinaryExpression[operator='in']"() {
|
||
|
|
let info = funcInfo;
|
||
|
|
|
||
|
|
while (info) {
|
||
|
|
info.hasInOperator = true;
|
||
|
|
info = info.upper;
|
||
|
|
}
|
||
|
|
},
|
||
|
|
ArrowFunctionExpression() {
|
||
|
|
funcInfo = {
|
||
|
|
upper: funcInfo,
|
||
|
|
hasInOperator: false
|
||
|
|
};
|
||
|
|
},
|
||
|
|
"ArrowFunctionExpression:exit"(node) {
|
||
|
|
validate(node);
|
||
|
|
funcInfo = funcInfo.upper;
|
||
|
|
}
|
||
|
|
};
|
||
|
|
}
|
||
|
|
};
|