94 lines
3.8 KiB
JavaScript
94 lines
3.8 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 tsutils_1 = require("tsutils");
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var ts = require("typescript");
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var Lint = require("../index");
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var utils_1 = require("../language/utils");
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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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Rule.prototype.apply = function (sourceFile) {
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return this.applyWithFunction(sourceFile, walk);
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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: "binary-expression-operand-order",
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description: (_a = ["\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'."], _a.raw = ["\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'."], Lint.Utils.dedent(_a)),
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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: false,
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};
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/* tslint:enable:object-literal-sort-keys */
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Rule.FAILURE_STRING = "Literal expression should be on the right-hand side of a binary expression.";
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return Rule;
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}(Lint.Rules.AbstractRule));
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exports.Rule = Rule;
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function walk(ctx) {
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ts.forEachChild(ctx.sourceFile, function cb(node) {
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if (tsutils_1.isBinaryExpression(node) && isLiteral(node.left) && !isLiteral(node.right) && !isAllowedOrderedOperator(node)) {
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ctx.addFailureAtNode(node, Rule.FAILURE_STRING);
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}
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ts.forEachChild(node, cb);
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});
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}
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/** Allows certain inherently ordered operators that can't easily be written with the literal on the right. */
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function isAllowedOrderedOperator(node) {
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switch (node.operatorToken.kind) {
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case ts.SyntaxKind.PlusToken:
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// Allow `"foo" + x` but not `1 + x`.
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return node.left.kind === ts.SyntaxKind.StringLiteral;
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case ts.SyntaxKind.MinusToken:
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case ts.SyntaxKind.SlashToken:
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case ts.SyntaxKind.PercentToken:
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case ts.SyntaxKind.LessThanLessThanToken:
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case ts.SyntaxKind.GreaterThanGreaterThanToken:
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case ts.SyntaxKind.GreaterThanGreaterThanGreaterThanToken:
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case ts.SyntaxKind.AsteriskAsteriskToken:
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case ts.SyntaxKind.InKeyword:
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case ts.SyntaxKind.CommaToken:
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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 isLiteral(node) {
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switch (node.kind) {
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case ts.SyntaxKind.StringLiteral:
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case ts.SyntaxKind.NumericLiteral:
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case ts.SyntaxKind.TrueKeyword:
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case ts.SyntaxKind.FalseKeyword:
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case ts.SyntaxKind.NullKeyword:
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return true;
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case ts.SyntaxKind.Identifier:
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return node.originalKeywordKind === ts.SyntaxKind.UndefinedKeyword;
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case ts.SyntaxKind.PrefixUnaryExpression:
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return utils_1.isNegativeNumberLiteral(node);
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case ts.SyntaxKind.ParenthesizedExpression:
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return isLiteral(node.expression);
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default:
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return false;
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}
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}
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var _a;
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