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"use strict";
/**
* @license
* Copyright 2017 Palantir Technologies, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
Object.defineProperty(exports, "__esModule", { value: true });
var tslib_1 = require("tslib");
var utils = require("tsutils");
var ts = require("typescript");
var Lint = require("../index");
var Rule = (function (_super) {
tslib_1.__extends(Rule, _super);
function Rule() {
return _super !== null && _super.apply(this, arguments) || this;
}
/* tslint:enable:object-literal-sort-keys */
Rule.FAILURE_STRING = function (negate) {
return "This expression is unnecessarily compared to a boolean. Just " + (negate ? "negate it" : "use it directly") + ".";
};
Rule.prototype.applyWithProgram = function (sourceFile, program) {
return this.applyWithFunction(sourceFile, function (ctx) { return walk(ctx, program.getTypeChecker()); });
};
/* tslint:disable:object-literal-sort-keys */
Rule.metadata = {
ruleName: "no-boolean-literal-compare",
description: "Warns on comparison to a boolean literal, as in `x === true`.",
hasFix: true,
optionsDescription: "Not configurable.",
options: null,
optionExamples: [true],
type: "style",
typescriptOnly: true,
requiresTypeInfo: true,
};
return Rule;
}(Lint.Rules.TypedRule));
exports.Rule = Rule;
function walk(ctx, checker) {
return ts.forEachChild(ctx.sourceFile, function cb(node) {
if (utils.isBinaryExpression(node)) {
var cmp = getBooleanComparison(node, checker);
if (cmp !== undefined) {
ctx.addFailureAtNode(cmp.expression, Rule.FAILURE_STRING(cmp.negate), fix(node, cmp));
}
}
return ts.forEachChild(node, cb);
});
}
function getBooleanComparison(node, checker) {
var cmp = deconstructComparison(node);
return cmp === undefined || !Lint.isTypeFlagSet(checker.getTypeAtLocation(cmp.expression), ts.TypeFlags.Boolean) ? undefined : cmp;
}
function fix(node, _a) {
var negate = _a.negate, expression = _a.expression;
var deleted = node.left === expression
? Lint.Replacement.deleteFromTo(node.left.end, node.end)
: Lint.Replacement.deleteFromTo(node.getStart(), node.right.getStart());
if (!negate) {
return deleted;
}
else if (needsParenthesesForNegate(expression)) {
return [
deleted,
Lint.Replacement.appendText(node.getStart(), "!("),
Lint.Replacement.appendText(node.getEnd(), ")"),
];
}
else {
return [
deleted,
Lint.Replacement.appendText(node.getStart(), "!"),
];
}
}
function needsParenthesesForNegate(node) {
switch (node.kind) {
case ts.SyntaxKind.AsExpression:
case ts.SyntaxKind.BinaryExpression:
return true;
default:
return false;
}
}
function deconstructComparison(node) {
var left = node.left, operatorToken = node.operatorToken, right = node.right;
var eq = Lint.getEqualsKind(operatorToken);
if (eq === undefined) {
return undefined;
}
var leftValue = booleanFromExpression(left);
if (leftValue !== undefined) {
return { negate: leftValue !== eq.isPositive, expression: right };
}
var rightValue = booleanFromExpression(right);
if (rightValue !== undefined) {
return { negate: rightValue !== eq.isPositive, expression: left };
}
return undefined;
}
function booleanFromExpression(node) {
switch (node.kind) {
case ts.SyntaxKind.TrueKeyword:
return true;
case ts.SyntaxKind.FalseKeyword:
return false;
default:
return undefined;
}
}
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