useIsnanRule.js
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"use strict";
var __extends = (this && this.__extends) || function (d, b) {
for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p];
function __() { this.constructor = d; }
d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
};
var ts = require("typescript");
var Lint = require("../lint");
var Rule = (function (_super) {
__extends(Rule, _super);
function Rule() {
_super.apply(this, arguments);
}
Rule.prototype.apply = function (sourceFile) {
return this.applyWithWalker(new UseIsnanRuleWalker(sourceFile, this.getOptions()));
};
Rule.metadata = {
ruleName: "use-isnan",
description: "Enforces use of the `isNaN()` function to check for NaN references instead of a comparison to the `NaN` constant.",
rationale: (_a = ["\n Since `NaN !== NaN`, comparisons with regular operators will produce unexpected results.\n So, instead of `if (myVar === NaN)`, do `if (isNaN(myVar))`."], _a.raw = ["\n Since \\`NaN !== NaN\\`, comparisons with regular operators will produce unexpected results.\n So, instead of \\`if (myVar === NaN)\\`, do \\`if (isNaN(myVar))\\`."], Lint.Utils.dedent(_a)),
optionsDescription: "Not configurable.",
options: null,
optionExamples: ["true"],
type: "functionality",
};
Rule.FAILURE_STRING = "Found an invalid comparison for NaN: ";
return Rule;
var _a;
}(Lint.Rules.AbstractRule));
exports.Rule = Rule;
var UseIsnanRuleWalker = (function (_super) {
__extends(UseIsnanRuleWalker, _super);
function UseIsnanRuleWalker() {
_super.apply(this, arguments);
}
UseIsnanRuleWalker.prototype.visitBinaryExpression = function (node) {
if ((this.isExpressionNaN(node.left) || this.isExpressionNaN(node.right))
&& node.operatorToken.kind !== ts.SyntaxKind.EqualsToken) {
this.addFailure(this.createFailure(node.getStart(), node.getWidth(), Rule.FAILURE_STRING + node.getText()));
}
_super.prototype.visitBinaryExpression.call(this, node);
};
UseIsnanRuleWalker.prototype.isExpressionNaN = function (node) {
return node.kind === ts.SyntaxKind.Identifier && node.getText() === "NaN";
};
return UseIsnanRuleWalker;
}(Lint.RuleWalker));