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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 tsutils_1 = require("tsutils");
- var ts = require("typescript");
- var Lint = require("../index");
- var utils_1 = require("../language/utils");
- var Rule = /** @class */ (function (_super) {
- tslib_1.__extends(Rule, _super);
- function Rule() {
- return _super !== null && _super.apply(this, arguments) || this;
- }
- Rule.prototype.apply = function (sourceFile) {
- return this.applyWithFunction(sourceFile, walk);
- };
- /* tslint:disable:object-literal-sort-keys */
- Rule.metadata = {
- ruleName: "binary-expression-operand-order",
- description: Lint.Utils.dedent(templateObject_1 || (templateObject_1 = tslib_1.__makeTemplateObject(["\n In a binary expression, a literal should always be on the right-hand side if possible.\n For example, prefer 'x + 1' over '1 + x'."], ["\n In a binary expression, a literal should always be on the right-hand side if possible.\n For example, prefer 'x + 1' over '1 + x'."]))),
- optionsDescription: "Not configurable.",
- options: null,
- optionExamples: [true],
- rationale: Lint.Utils.dedent(templateObject_2 || (templateObject_2 = tslib_1.__makeTemplateObject(["\n Expressions like `1 + x` are sometimes referred to as \"Yoda\" expressions because they read\n opposite to how we would normally speak the expression.\n\n Sticking to a consistent grammar for conditions helps keep code readable and understandable.\n "], ["\n Expressions like \\`1 + x\\` are sometimes referred to as \"Yoda\" expressions because they read\n opposite to how we would normally speak the expression.\n\n Sticking to a consistent grammar for conditions helps keep code readable and understandable.\n "]))),
- type: "style",
- typescriptOnly: false,
- };
- /* tslint:enable:object-literal-sort-keys */
- Rule.FAILURE_STRING = "Literal expression should be on the right-hand side of a binary expression.";
- return Rule;
- }(Lint.Rules.AbstractRule));
- exports.Rule = Rule;
- function walk(ctx) {
- ts.forEachChild(ctx.sourceFile, function cb(node) {
- if (tsutils_1.isBinaryExpression(node) && isLiteral(node.left) && !isLiteral(node.right) && !isAllowedOrderedOperator(node)) {
- ctx.addFailureAtNode(node, Rule.FAILURE_STRING);
- }
- ts.forEachChild(node, cb);
- });
- }
- /** Allows certain inherently ordered operators that can't easily be written with the literal on the right. */
- function isAllowedOrderedOperator(node) {
- switch (node.operatorToken.kind) {
- case ts.SyntaxKind.PlusToken:
- // Allow `"foo" + x` but not `1 + x`.
- return node.left.kind === ts.SyntaxKind.StringLiteral;
- case ts.SyntaxKind.MinusToken:
- case ts.SyntaxKind.SlashToken:
- case ts.SyntaxKind.PercentToken:
- case ts.SyntaxKind.LessThanLessThanToken:
- case ts.SyntaxKind.GreaterThanGreaterThanToken:
- case ts.SyntaxKind.GreaterThanGreaterThanGreaterThanToken:
- case ts.SyntaxKind.AsteriskAsteriskToken:
- case ts.SyntaxKind.InKeyword:
- case ts.SyntaxKind.CommaToken:
- return true;
- default:
- return false;
- }
- }
- function isLiteral(node) {
- switch (node.kind) {
- case ts.SyntaxKind.StringLiteral:
- case ts.SyntaxKind.NumericLiteral:
- case ts.SyntaxKind.TrueKeyword:
- case ts.SyntaxKind.FalseKeyword:
- case ts.SyntaxKind.NullKeyword:
- return true;
- case ts.SyntaxKind.Identifier:
- return node.originalKeywordKind === ts.SyntaxKind.UndefinedKeyword;
- case ts.SyntaxKind.PrefixUnaryExpression:
- return utils_1.isNegativeNumberLiteral(node);
- case ts.SyntaxKind.ParenthesizedExpression:
- return isLiteral(node.expression);
- default:
- return false;
- }
- }
- var templateObject_1, templateObject_2;
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