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codeql-action/node_modules/eslint/lib/rules/no-extra-bind.js
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/** | |
* @fileoverview Rule to flag unnecessary bind calls | |
* @author Bence Dányi <bence@danyi.me> | |
*/ | |
"use strict"; | |
//------------------------------------------------------------------------------ | |
// Requirements | |
//------------------------------------------------------------------------------ | |
const astUtils = require("./utils/ast-utils"); | |
//------------------------------------------------------------------------------ | |
// Helpers | |
//------------------------------------------------------------------------------ | |
const SIDE_EFFECT_FREE_NODE_TYPES = new Set(["Literal", "Identifier", "ThisExpression", "FunctionExpression"]); | |
//------------------------------------------------------------------------------ | |
// Rule Definition | |
//------------------------------------------------------------------------------ | |
/** @type {import('../shared/types').Rule} */ | |
module.exports = { | |
meta: { | |
type: "suggestion", | |
docs: { | |
description: "Disallow unnecessary calls to `.bind()`", | |
recommended: false, | |
url: "https://eslint.org/docs/latest/rules/no-extra-bind" | |
}, | |
schema: [], | |
fixable: "code", | |
messages: { | |
unexpected: "The function binding is unnecessary." | |
} | |
}, | |
create(context) { | |
const sourceCode = context.sourceCode; | |
let scopeInfo = null; | |
/** | |
* Checks if a node is free of side effects. | |
* | |
* This check is stricter than it needs to be, in order to keep the implementation simple. | |
* @param {ASTNode} node A node to check. | |
* @returns {boolean} True if the node is known to be side-effect free, false otherwise. | |
*/ | |
function isSideEffectFree(node) { | |
return SIDE_EFFECT_FREE_NODE_TYPES.has(node.type); | |
} | |
/** | |
* Reports a given function node. | |
* @param {ASTNode} node A node to report. This is a FunctionExpression or | |
* an ArrowFunctionExpression. | |
* @returns {void} | |
*/ | |
function report(node) { | |
const memberNode = node.parent; | |
const callNode = memberNode.parent.type === "ChainExpression" | |
? memberNode.parent.parent | |
: memberNode.parent; | |
context.report({ | |
node: callNode, | |
messageId: "unexpected", | |
loc: memberNode.property.loc, | |
fix(fixer) { | |
if (!isSideEffectFree(callNode.arguments[0])) { | |
return null; | |
} | |
/* | |
* The list of the first/last token pair of a removal range. | |
* This is two parts because closing parentheses may exist between the method name and arguments. | |
* E.g. `(function(){}.bind ) (obj)` | |
* ^^^^^ ^^^^^ < removal ranges | |
* E.g. `(function(){}?.['bind'] ) ?.(obj)` | |
* ^^^^^^^^^^ ^^^^^^^ < removal ranges | |
*/ | |
const tokenPairs = [ | |
[ | |
// `.`, `?.`, or `[` token. | |
sourceCode.getTokenAfter( | |
memberNode.object, | |
astUtils.isNotClosingParenToken | |
), | |
// property name or `]` token. | |
sourceCode.getLastToken(memberNode) | |
], | |
[ | |
// `?.` or `(` token of arguments. | |
sourceCode.getTokenAfter( | |
memberNode, | |
astUtils.isNotClosingParenToken | |
), | |
// `)` token of arguments. | |
sourceCode.getLastToken(callNode) | |
] | |
]; | |
const firstTokenToRemove = tokenPairs[0][0]; | |
const lastTokenToRemove = tokenPairs[1][1]; | |
if (sourceCode.commentsExistBetween(firstTokenToRemove, lastTokenToRemove)) { | |
return null; | |
} | |
return tokenPairs.map(([start, end]) => | |
fixer.removeRange([start.range[0], end.range[1]])); | |
} | |
}); | |
} | |
/** | |
* Checks whether or not a given function node is the callee of `.bind()` | |
* method. | |
* | |
* e.g. `(function() {}.bind(foo))` | |
* @param {ASTNode} node A node to report. This is a FunctionExpression or | |
* an ArrowFunctionExpression. | |
* @returns {boolean} `true` if the node is the callee of `.bind()` method. | |
*/ | |
function isCalleeOfBindMethod(node) { | |
if (!astUtils.isSpecificMemberAccess(node.parent, null, "bind")) { | |
return false; | |
} | |
// The node of `*.bind` member access. | |
const bindNode = node.parent.parent.type === "ChainExpression" | |
? node.parent.parent | |
: node.parent; | |
return ( | |
bindNode.parent.type === "CallExpression" && | |
bindNode.parent.callee === bindNode && | |
bindNode.parent.arguments.length === 1 && | |
bindNode.parent.arguments[0].type !== "SpreadElement" | |
); | |
} | |
/** | |
* Adds a scope information object to the stack. | |
* @param {ASTNode} node A node to add. This node is a FunctionExpression | |
* or a FunctionDeclaration node. | |
* @returns {void} | |
*/ | |
function enterFunction(node) { | |
scopeInfo = { | |
isBound: isCalleeOfBindMethod(node), | |
thisFound: false, | |
upper: scopeInfo | |
}; | |
} | |
/** | |
* Removes the scope information object from the top of the stack. | |
* At the same time, this reports the function node if the function has | |
* `.bind()` and the `this` keywords found. | |
* @param {ASTNode} node A node to remove. This node is a | |
* FunctionExpression or a FunctionDeclaration node. | |
* @returns {void} | |
*/ | |
function exitFunction(node) { | |
if (scopeInfo.isBound && !scopeInfo.thisFound) { | |
report(node); | |
} | |
scopeInfo = scopeInfo.upper; | |
} | |
/** | |
* Reports a given arrow function if the function is callee of `.bind()` | |
* method. | |
* @param {ASTNode} node A node to report. This node is an | |
* ArrowFunctionExpression. | |
* @returns {void} | |
*/ | |
function exitArrowFunction(node) { | |
if (isCalleeOfBindMethod(node)) { | |
report(node); | |
} | |
} | |
/** | |
* Set the mark as the `this` keyword was found in this scope. | |
* @returns {void} | |
*/ | |
function markAsThisFound() { | |
if (scopeInfo) { | |
scopeInfo.thisFound = true; | |
} | |
} | |
return { | |
"ArrowFunctionExpression:exit": exitArrowFunction, | |
FunctionDeclaration: enterFunction, | |
"FunctionDeclaration:exit": exitFunction, | |
FunctionExpression: enterFunction, | |
"FunctionExpression:exit": exitFunction, | |
ThisExpression: markAsThisFound | |
}; | |
} | |
}; |