node/tools/node_modules/eslint/lib/rules/no-eq-null.js
Michaël Zasso 3dc3063275 tools: move eslint from tools to tools/node_modules
This is required because we need to add the babel-eslint dependency
and it has to be able to resolve "eslint".
babel-eslint is required to support future ES features such as async
iterators and import.meta.

Refs: https://github.com/nodejs/node/pull/17755
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 09:48:05 +01:00

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/**
* @fileoverview Rule to flag comparisons to null without a type-checking
* operator.
* @author Ian Christian Myers
*/
"use strict";
//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------
module.exports = {
meta: {
docs: {
description: "disallow `null` comparisons without type-checking operators",
category: "Best Practices",
recommended: false
},
schema: []
},
create(context) {
return {
BinaryExpression(node) {
const badOperator = node.operator === "==" || node.operator === "!=";
if (node.right.type === "Literal" && node.right.raw === "null" && badOperator ||
node.left.type === "Literal" && node.left.raw === "null" && badOperator) {
context.report({ node, message: "Use === to compare with null." });
}
}
};
}
};