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178 lines
6.4 KiB
178 lines
6.4 KiB
/** |
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* @fileoverview Rule to flag adding properties to native object's prototypes. |
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* @author David Nelson |
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*/ |
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"use strict"; |
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//------------------------------------------------------------------------------ |
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// Requirements |
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//------------------------------------------------------------------------------ |
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const astUtils = require("./utils/ast-utils"); |
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const globals = require("globals"); |
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//------------------------------------------------------------------------------ |
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// Rule Definition |
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//------------------------------------------------------------------------------ |
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/** @type {import('../shared/types').Rule} */ |
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module.exports = { |
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meta: { |
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type: "suggestion", |
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docs: { |
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description: "Disallow extending native types", |
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recommended: false, |
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url: "https://eslint.org/docs/rules/no-extend-native" |
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}, |
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schema: [ |
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{ |
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type: "object", |
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properties: { |
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exceptions: { |
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type: "array", |
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items: { |
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type: "string" |
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}, |
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uniqueItems: true |
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} |
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}, |
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additionalProperties: false |
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} |
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], |
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messages: { |
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unexpected: "{{builtin}} prototype is read only, properties should not be added." |
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} |
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}, |
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create(context) { |
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const config = context.options[0] || {}; |
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const exceptions = new Set(config.exceptions || []); |
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const modifiedBuiltins = new Set( |
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Object.keys(globals.builtin) |
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.filter(builtin => builtin[0].toUpperCase() === builtin[0]) |
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.filter(builtin => !exceptions.has(builtin)) |
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); |
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/** |
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* Reports a lint error for the given node. |
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* @param {ASTNode} node The node to report. |
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* @param {string} builtin The name of the native builtin being extended. |
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* @returns {void} |
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*/ |
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function reportNode(node, builtin) { |
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context.report({ |
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node, |
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messageId: "unexpected", |
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data: { |
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builtin |
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} |
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}); |
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} |
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/** |
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* Check to see if the `prototype` property of the given object |
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* identifier node is being accessed. |
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* @param {ASTNode} identifierNode The Identifier representing the object |
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* to check. |
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* @returns {boolean} True if the identifier is the object of a |
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* MemberExpression and its `prototype` property is being accessed, |
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* false otherwise. |
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*/ |
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function isPrototypePropertyAccessed(identifierNode) { |
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return Boolean( |
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identifierNode && |
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identifierNode.parent && |
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identifierNode.parent.type === "MemberExpression" && |
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identifierNode.parent.object === identifierNode && |
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astUtils.getStaticPropertyName(identifierNode.parent) === "prototype" |
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); |
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} |
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/** |
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* Check if it's an assignment to the property of the given node. |
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* Example: `*.prop = 0` // the `*` is the given node. |
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* @param {ASTNode} node The node to check. |
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* @returns {boolean} True if an assignment to the property of the node. |
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*/ |
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function isAssigningToPropertyOf(node) { |
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return ( |
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node.parent.type === "MemberExpression" && |
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node.parent.object === node && |
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node.parent.parent.type === "AssignmentExpression" && |
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node.parent.parent.left === node.parent |
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); |
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} |
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/** |
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* Checks if the given node is at the first argument of the method call of `Object.defineProperty()` or `Object.defineProperties()`. |
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* @param {ASTNode} node The node to check. |
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* @returns {boolean} True if the node is at the first argument of the method call of `Object.defineProperty()` or `Object.defineProperties()`. |
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*/ |
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function isInDefinePropertyCall(node) { |
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return ( |
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node.parent.type === "CallExpression" && |
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node.parent.arguments[0] === node && |
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astUtils.isSpecificMemberAccess(node.parent.callee, "Object", /^definePropert(?:y|ies)$/u) |
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); |
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} |
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/** |
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* Check to see if object prototype access is part of a prototype |
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* extension. There are three ways a prototype can be extended: |
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* 1. Assignment to prototype property (Object.prototype.foo = 1) |
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* 2. Object.defineProperty()/Object.defineProperties() on a prototype |
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* If prototype extension is detected, report the AssignmentExpression |
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* or CallExpression node. |
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* @param {ASTNode} identifierNode The Identifier representing the object |
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* which prototype is being accessed and possibly extended. |
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* @returns {void} |
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*/ |
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function checkAndReportPrototypeExtension(identifierNode) { |
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if (!isPrototypePropertyAccessed(identifierNode)) { |
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return; // This is not `*.prototype` access. |
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} |
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/* |
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* `identifierNode.parent` is a MemberExpression `*.prototype`. |
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* If it's an optional member access, it may be wrapped by a `ChainExpression` node. |
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*/ |
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const prototypeNode = |
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identifierNode.parent.parent.type === "ChainExpression" |
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? identifierNode.parent.parent |
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: identifierNode.parent; |
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if (isAssigningToPropertyOf(prototypeNode)) { |
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// `*.prototype` -> MemberExpression -> AssignmentExpression |
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reportNode(prototypeNode.parent.parent, identifierNode.name); |
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} else if (isInDefinePropertyCall(prototypeNode)) { |
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// `*.prototype` -> CallExpression |
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reportNode(prototypeNode.parent, identifierNode.name); |
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} |
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} |
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return { |
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"Program:exit"() { |
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const globalScope = context.getScope(); |
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modifiedBuiltins.forEach(builtin => { |
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const builtinVar = globalScope.set.get(builtin); |
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if (builtinVar && builtinVar.references) { |
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builtinVar.references |
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.map(ref => ref.identifier) |
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.forEach(checkAndReportPrototypeExtension); |
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} |
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}); |
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} |
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}; |
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} |
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};
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