117 lines
5.4 KiB
JavaScript
117 lines
5.4 KiB
JavaScript
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"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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exports.Rule = void 0;
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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 OPTION_CHECK_ELSE_IF = "check-else-if";
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var Rule = /** @class */ (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 (assigned) {
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return "Use a conditional expression instead of assigning to '" + assigned + "' in multiple places.";
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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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checkElseIf: this.ruleArguments.indexOf(OPTION_CHECK_ELSE_IF) !== -1,
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});
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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: "prefer-conditional-expression",
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description: Lint.Utils.dedent(templateObject_1 || (templateObject_1 = tslib_1.__makeTemplateObject(["\n Recommends to use a conditional expression instead of assigning to the same thing in each branch of an if statement."], ["\n Recommends to use a conditional expression instead of assigning to the same thing in each branch of an if statement."]))),
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rationale: Lint.Utils.dedent(templateObject_2 || (templateObject_2 = tslib_1.__makeTemplateObject(["\n This reduces duplication and can eliminate an unnecessary variable declaration."], ["\n This reduces duplication and can eliminate an unnecessary variable declaration."]))),
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optionsDescription: "If `" + OPTION_CHECK_ELSE_IF + "` is specified, the rule also checks nested if-else-if statements.",
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options: {
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type: "string",
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enum: [OPTION_CHECK_ELSE_IF],
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},
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optionExamples: [true, [true, OPTION_CHECK_ELSE_IF]],
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type: "functionality",
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typescriptOnly: false,
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};
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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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var sourceFile = ctx.sourceFile, checkElseIf = ctx.options.checkElseIf;
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return ts.forEachChild(sourceFile, function cb(node) {
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if (tsutils_1.isIfStatement(node)) {
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var assigned = detectAssignment(node, sourceFile, checkElseIf);
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if (assigned !== undefined) {
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ctx.addFailureAtNode(node.getChildAt(0, sourceFile), Rule.FAILURE_STRING(assigned.getText(sourceFile)));
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}
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if (assigned !== undefined || !checkElseIf) {
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// Be careful not to fail again for the "else if"
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do {
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ts.forEachChild(node.expression, cb);
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ts.forEachChild(node.thenStatement, cb);
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if (node.elseStatement === undefined) {
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return;
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}
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node = node.elseStatement;
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while (tsutils_1.isBlock(node) && node.statements.length === 1) {
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node = node.statements[0];
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}
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} while (tsutils_1.isIfStatement(node));
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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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/**
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* @param inElse `undefined` when this is the top level if statement, `false` when inside the then branch, `true` when inside else
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*/
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function detectAssignment(statement, sourceFile, checkElseIf, inElse) {
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if (tsutils_1.isIfStatement(statement)) {
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if (inElse === false || (!checkElseIf && inElse) || statement.elseStatement === undefined) {
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return undefined;
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}
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var then = detectAssignment(statement.thenStatement, sourceFile, checkElseIf, false);
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if (then === undefined) {
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return undefined;
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}
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var elze = detectAssignment(statement.elseStatement, sourceFile, checkElseIf, true);
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return elze !== undefined && nodeEquals(then, elze, sourceFile) ? then : undefined;
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}
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else if (tsutils_1.isBlock(statement)) {
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return statement.statements.length === 1
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? detectAssignment(statement.statements[0], sourceFile, checkElseIf, inElse)
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: undefined;
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}
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else if (tsutils_1.isExpressionStatement(statement) && tsutils_1.isBinaryExpression(statement.expression)) {
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var _a = statement.expression, kind = _a.operatorToken.kind, left = _a.left, right = _a.right;
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return kind === ts.SyntaxKind.EqualsToken &&
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tsutils_1.isSameLine(sourceFile, right.getStart(sourceFile), right.end)
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? left
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: undefined;
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}
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else {
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return undefined;
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}
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}
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function nodeEquals(a, b, sourceFile) {
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return a.getText(sourceFile) === b.getText(sourceFile);
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}
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var templateObject_1, templateObject_2;
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