node/tools/node_modules/eslint/lib/rules/no-compare-neg-zero.js
Michaël Zasso 7a52c51e81 tools: update ESLint to 4.15.0
PR-URL: https://github.com/nodejs/node/pull/17820
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
2018-01-11 09:50:42 +01:00

55 lines
1.8 KiB
JavaScript

/**
* @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: {
docs: {
description: "disallow comparing against -0",
category: "Possible Errors",
recommended: true,
url: "https://eslint.org/docs/rules/no-compare-neg-zero"
},
fixable: null,
schema: []
},
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,
message: "Do not use the '{{operator}}' operator to compare against -0.",
data: { operator: node.operator }
});
}
}
}
};
}
};