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128 lines
4.6 KiB
128 lines
4.6 KiB
/** |
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* @fileoverview Rule to disallow negating the left operand of relational operators |
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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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// Requirements |
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//------------------------------------------------------------------------------ |
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const astUtils = require("./utils/ast-utils"); |
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//------------------------------------------------------------------------------ |
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// Helpers |
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//------------------------------------------------------------------------------ |
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/** |
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* Checks whether the given operator is `in` or `instanceof` |
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* @param {string} op The operator type to check. |
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* @returns {boolean} `true` if the operator is `in` or `instanceof` |
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*/ |
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function isInOrInstanceOfOperator(op) { |
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return op === "in" || op === "instanceof"; |
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} |
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/** |
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* Checks whether the given operator is an ordering relational operator or not. |
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* @param {string} op The operator type to check. |
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* @returns {boolean} `true` if the operator is an ordering relational operator. |
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*/ |
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function isOrderingRelationalOperator(op) { |
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return op === "<" || op === ">" || op === ">=" || op === "<="; |
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} |
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/** |
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* Checks whether the given node is a logical negation expression or not. |
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* @param {ASTNode} node The node to check. |
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* @returns {boolean} `true` if the node is a logical negation expression. |
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*/ |
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function isNegation(node) { |
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return node.type === "UnaryExpression" && node.operator === "!"; |
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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 negating the left operand of relational operators", |
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recommended: true, |
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url: "https://eslint.org/docs/rules/no-unsafe-negation" |
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}, |
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hasSuggestions: true, |
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schema: [ |
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{ |
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type: "object", |
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properties: { |
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enforceForOrderingRelations: { |
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type: "boolean", |
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default: false |
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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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fixable: null, |
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messages: { |
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unexpected: "Unexpected negating the left operand of '{{operator}}' operator.", |
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suggestNegatedExpression: "Negate '{{operator}}' expression instead of its left operand. This changes the current behavior.", |
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suggestParenthesisedNegation: "Wrap negation in '()' to make the intention explicit. This preserves the current behavior." |
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} |
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}, |
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create(context) { |
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const sourceCode = context.getSourceCode(); |
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const options = context.options[0] || {}; |
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const enforceForOrderingRelations = options.enforceForOrderingRelations === true; |
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return { |
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BinaryExpression(node) { |
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const operator = node.operator; |
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const orderingRelationRuleApplies = enforceForOrderingRelations && isOrderingRelationalOperator(operator); |
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if ( |
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(isInOrInstanceOfOperator(operator) || orderingRelationRuleApplies) && |
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isNegation(node.left) && |
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!astUtils.isParenthesised(sourceCode, node.left) |
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) { |
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context.report({ |
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node, |
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loc: node.left.loc, |
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messageId: "unexpected", |
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data: { operator }, |
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suggest: [ |
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{ |
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messageId: "suggestNegatedExpression", |
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data: { operator }, |
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fix(fixer) { |
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const negationToken = sourceCode.getFirstToken(node.left); |
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const fixRange = [negationToken.range[1], node.range[1]]; |
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const text = sourceCode.text.slice(fixRange[0], fixRange[1]); |
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return fixer.replaceTextRange(fixRange, `(${text})`); |
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} |
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}, |
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{ |
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messageId: "suggestParenthesisedNegation", |
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fix(fixer) { |
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return fixer.replaceText(node.left, `(${sourceCode.getText(node.left)})`); |
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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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};
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