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115 lines
3.3 KiB
115 lines
3.3 KiB
/** |
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* @fileoverview Rule to |
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* @author Toru Nagashima |
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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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/** |
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* Gets the variable object of `arguments` which is defined implicitly. |
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* @param {eslint-scope.Scope} scope A scope to get. |
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* @returns {eslint-scope.Variable} The found variable object. |
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*/ |
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function getVariableOfArguments(scope) { |
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const variables = scope.variables; |
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for (let i = 0; i < variables.length; ++i) { |
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const variable = variables[i]; |
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if (variable.name === "arguments") { |
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/* |
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* If there was a parameter which is named "arguments", the implicit "arguments" is not defined. |
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* So does fast return with null. |
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*/ |
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return (variable.identifiers.length === 0) ? variable : null; |
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} |
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} |
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/* istanbul ignore next : unreachable */ |
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return null; |
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} |
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/** |
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* Checks if the given reference is not normal member access. |
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* |
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* - arguments .... true // not member access |
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* - arguments[i] .... true // computed member access |
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* - arguments[0] .... true // computed member access |
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* - arguments.length .... false // normal member access |
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* @param {eslint-scope.Reference} reference The reference to check. |
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* @returns {boolean} `true` if the reference is not normal member access. |
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*/ |
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function isNotNormalMemberAccess(reference) { |
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const id = reference.identifier; |
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const parent = id.parent; |
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return !( |
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parent.type === "MemberExpression" && |
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parent.object === id && |
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!parent.computed |
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); |
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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: "suggestion", |
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docs: { |
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description: "Require rest parameters instead of `arguments`", |
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recommended: false, |
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url: "https://eslint.org/docs/rules/prefer-rest-params" |
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}, |
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schema: [], |
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messages: { |
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preferRestParams: "Use the rest parameters instead of 'arguments'." |
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} |
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}, |
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create(context) { |
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/** |
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* Reports a given reference. |
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* @param {eslint-scope.Reference} reference A reference to report. |
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* @returns {void} |
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*/ |
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function report(reference) { |
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context.report({ |
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node: reference.identifier, |
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loc: reference.identifier.loc, |
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messageId: "preferRestParams" |
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}); |
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} |
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/** |
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* Reports references of the implicit `arguments` variable if exist. |
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* @returns {void} |
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*/ |
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function checkForArguments() { |
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const argumentsVar = getVariableOfArguments(context.getScope()); |
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if (argumentsVar) { |
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argumentsVar |
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.references |
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.filter(isNotNormalMemberAccess) |
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.forEach(report); |
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} |
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} |
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return { |
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"FunctionDeclaration:exit": checkForArguments, |
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"FunctionExpression:exit": checkForArguments |
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}; |
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} |
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};
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