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647 BJavaScriptView Raw
1/**
2 * @fileoverview A rule to disallow negated left operands of the `in` operator
3 * @author Michael Ficarra
4 */
5
6//------------------------------------------------------------------------------
7// Rule Definition
8//------------------------------------------------------------------------------
9
10module.exports = function(context) {
11
12 "use strict";
13
14 return {
15
16 "BinaryExpression": function(node) {
17 if (node.operator === "in" && node.left.type === "UnaryExpression" && node.left.operator === "!") {
18 context.report(node, "The `in` expression's left operand is negated");
19 }
20 }
21 };
22
23};