61 lines
1.9 KiB
JavaScript
61 lines
1.9 KiB
JavaScript
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/**
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* @fileoverview The rule should warn against code that tries to compare against -0.
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* @author Aladdin-ADD <hh_2013@foxmail.com>
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*/
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"use strict";
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//------------------------------------------------------------------------------
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// Rule Definition
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//------------------------------------------------------------------------------
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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 comparing against -0",
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category: "Possible Errors",
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recommended: true,
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url: "https://eslint.org/docs/rules/no-compare-neg-zero"
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},
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fixable: null,
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schema: [],
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messages: {
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unexpected: "Do not use the '{{operator}}' operator to compare against -0."
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}
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},
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create(context) {
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//--------------------------------------------------------------------------
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// Helpers
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//--------------------------------------------------------------------------
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/**
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* Checks a given node is -0
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* @param {ASTNode} node A node to check.
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* @returns {boolean} `true` if the node is -0.
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*/
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function isNegZero(node) {
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return node.type === "UnaryExpression" && node.operator === "-" && node.argument.type === "Literal" && node.argument.value === 0;
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}
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const OPERATORS_TO_CHECK = new Set([">", ">=", "<", "<=", "==", "===", "!=", "!=="]);
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return {
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BinaryExpression(node) {
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if (OPERATORS_TO_CHECK.has(node.operator)) {
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if (isNegZero(node.left) || isNegZero(node.right)) {
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context.report({
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node,
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messageId: "unexpected",
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data: { operator: node.operator }
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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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