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