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239 lines
7.2 KiB
239 lines
7.2 KiB
/** |
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* @fileoverview Rule to flag updates of imported bindings. |
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* @author Toru Nagashima <https://github.com/mysticatea> |
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*/ |
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"use strict"; |
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//------------------------------------------------------------------------------ |
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// Helpers |
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//------------------------------------------------------------------------------ |
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const { findVariable } = require("eslint-utils"); |
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const astUtils = require("./utils/ast-utils"); |
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const WellKnownMutationFunctions = { |
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Object: /^(?:assign|definePropert(?:y|ies)|freeze|setPrototypeOf)$/u, |
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Reflect: /^(?:(?:define|delete)Property|set(?:PrototypeOf)?)$/u |
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}; |
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/** |
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* Check if a given node is LHS of an assignment node. |
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* @param {ASTNode} node The node to check. |
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* @returns {boolean} `true` if the node is LHS. |
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*/ |
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function isAssignmentLeft(node) { |
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const { parent } = node; |
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return ( |
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( |
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parent.type === "AssignmentExpression" && |
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parent.left === node |
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) || |
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// Destructuring assignments |
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parent.type === "ArrayPattern" || |
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( |
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parent.type === "Property" && |
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parent.value === node && |
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parent.parent.type === "ObjectPattern" |
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) || |
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parent.type === "RestElement" || |
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( |
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parent.type === "AssignmentPattern" && |
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parent.left === node |
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) |
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); |
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} |
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/** |
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* Check if a given node is the operand of mutation unary operator. |
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* @param {ASTNode} node The node to check. |
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* @returns {boolean} `true` if the node is the operand of mutation unary operator. |
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*/ |
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function isOperandOfMutationUnaryOperator(node) { |
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const argumentNode = node.parent.type === "ChainExpression" |
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? node.parent |
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: node; |
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const { parent } = argumentNode; |
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return ( |
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( |
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parent.type === "UpdateExpression" && |
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parent.argument === argumentNode |
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) || |
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( |
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parent.type === "UnaryExpression" && |
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parent.operator === "delete" && |
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parent.argument === argumentNode |
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) |
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); |
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} |
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/** |
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* Check if a given node is the iteration variable of `for-in`/`for-of` syntax. |
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* @param {ASTNode} node The node to check. |
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* @returns {boolean} `true` if the node is the iteration variable. |
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*/ |
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function isIterationVariable(node) { |
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const { parent } = node; |
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return ( |
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( |
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parent.type === "ForInStatement" && |
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parent.left === node |
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) || |
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( |
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parent.type === "ForOfStatement" && |
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parent.left === node |
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) |
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); |
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} |
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/** |
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* Check if a given node is at the first argument of a well-known mutation function. |
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* - `Object.assign` |
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* - `Object.defineProperty` |
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* - `Object.defineProperties` |
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* - `Object.freeze` |
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* - `Object.setPrototypeOf` |
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* - `Reflect.defineProperty` |
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* - `Reflect.deleteProperty` |
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* - `Reflect.set` |
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* - `Reflect.setPrototypeOf` |
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* @param {ASTNode} node The node to check. |
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* @param {Scope} scope A `escope.Scope` object to find variable (whichever). |
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* @returns {boolean} `true` if the node is at the first argument of a well-known mutation function. |
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*/ |
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function isArgumentOfWellKnownMutationFunction(node, scope) { |
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const { parent } = node; |
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if (parent.type !== "CallExpression" || parent.arguments[0] !== node) { |
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return false; |
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} |
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const callee = astUtils.skipChainExpression(parent.callee); |
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if ( |
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!astUtils.isSpecificMemberAccess(callee, "Object", WellKnownMutationFunctions.Object) && |
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!astUtils.isSpecificMemberAccess(callee, "Reflect", WellKnownMutationFunctions.Reflect) |
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) { |
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return false; |
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} |
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const variable = findVariable(scope, callee.object); |
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return variable !== null && variable.scope.type === "global"; |
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} |
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/** |
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* Check if the identifier node is placed at to update members. |
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* @param {ASTNode} id The Identifier node to check. |
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* @param {Scope} scope A `escope.Scope` object to find variable (whichever). |
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* @returns {boolean} `true` if the member of `id` was updated. |
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*/ |
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function isMemberWrite(id, scope) { |
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const { parent } = id; |
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return ( |
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( |
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parent.type === "MemberExpression" && |
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parent.object === id && |
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( |
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isAssignmentLeft(parent) || |
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isOperandOfMutationUnaryOperator(parent) || |
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isIterationVariable(parent) |
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) |
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) || |
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isArgumentOfWellKnownMutationFunction(id, scope) |
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); |
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} |
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/** |
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* Get the mutation node. |
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* @param {ASTNode} id The Identifier node to get. |
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* @returns {ASTNode} The mutation node. |
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*/ |
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function getWriteNode(id) { |
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let node = id.parent; |
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while ( |
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node && |
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node.type !== "AssignmentExpression" && |
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node.type !== "UpdateExpression" && |
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node.type !== "UnaryExpression" && |
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node.type !== "CallExpression" && |
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node.type !== "ForInStatement" && |
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node.type !== "ForOfStatement" |
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) { |
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node = node.parent; |
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} |
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return node || id; |
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} |
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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: "problem", |
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docs: { |
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description: "Disallow assigning to imported bindings", |
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recommended: true, |
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url: "https://eslint.org/docs/rules/no-import-assign" |
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}, |
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schema: [], |
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messages: { |
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readonly: "'{{name}}' is read-only.", |
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readonlyMember: "The members of '{{name}}' are read-only." |
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} |
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}, |
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create(context) { |
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return { |
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ImportDeclaration(node) { |
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const scope = context.getScope(); |
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for (const variable of context.getDeclaredVariables(node)) { |
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const shouldCheckMembers = variable.defs.some( |
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d => d.node.type === "ImportNamespaceSpecifier" |
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); |
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let prevIdNode = null; |
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for (const reference of variable.references) { |
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const idNode = reference.identifier; |
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/* |
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* AssignmentPattern (e.g. `[a = 0] = b`) makes two write |
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* references for the same identifier. This should skip |
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* the one of the two in order to prevent redundant reports. |
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*/ |
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if (idNode === prevIdNode) { |
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continue; |
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} |
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prevIdNode = idNode; |
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if (reference.isWrite()) { |
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context.report({ |
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node: getWriteNode(idNode), |
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messageId: "readonly", |
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data: { name: idNode.name } |
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}); |
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} else if (shouldCheckMembers && isMemberWrite(idNode, scope)) { |
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context.report({ |
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node: getWriteNode(idNode), |
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messageId: "readonlyMember", |
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data: { name: idNode.name } |
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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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} |
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};
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