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