"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 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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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: "prefer-object-spread",
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description: "Enforces the use of the ES2018 object spread operator over `Object.assign()` where appropriate.",
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rationale: "Object spread allows for better type checking and inference.",
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optionsDescription: "Not configurable.",
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options: null,
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optionExamples: [true],
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type: "functionality",
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typescriptOnly: false,
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hasFix: true,
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};
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/* tslint:enable:object-literal-sort-keys */
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Rule.FAILURE_STRING = "Use the object spread operator instead.";
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Rule.ASSIGNMENT_FAILURE_STRING = "'Object.assign' returns the first argument. Prefer object spread if you want a new object.";
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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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return ts.forEachChild(ctx.sourceFile, function cb(node) {
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if (tsutils_1.isCallExpression(node) &&
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node.arguments.length !== 0 &&
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tsutils_1.isPropertyAccessExpression(node.expression) &&
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node.expression.name.text === "assign" &&
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tsutils_1.isIdentifier(node.expression.expression) &&
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node.expression.expression.text === "Object" &&
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!ts.isFunctionLike(node.arguments[0]) &&
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// Object.assign(...someArray) cannot be written as object spread
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!node.arguments.some(tsutils_1.isSpreadElement) &&
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/**
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* @TODO
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* Remove !node.arguments.some(isThisKeyword) when typescript get's
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* support for spread types.
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* PR: https://github.com/Microsoft/TypeScript/issues/10727
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*/
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!node.arguments.some(isThisKeyword)) {
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if (node.arguments[0].kind === ts.SyntaxKind.ObjectLiteralExpression) {
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ctx.addFailureAtNode(node, Rule.FAILURE_STRING, createFix(node, ctx.sourceFile));
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}
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else if (tsutils_1.isExpressionValueUsed(node) &&
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!tsutils_1.hasSideEffects(node.arguments[0], 2 /* Constructor */)) {
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ctx.addFailureAtNode(node, Rule.ASSIGNMENT_FAILURE_STRING, createFix(node, ctx.sourceFile));
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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 createFix(node, sourceFile) {
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var args = node.arguments;
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var objectNeedsParens = node.parent.kind === ts.SyntaxKind.ArrowFunction;
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var fix = [
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Lint.Replacement.replaceFromTo(node.getStart(sourceFile), args[0].getStart(sourceFile), (objectNeedsParens ? "(" : "") + "{"),
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new Lint.Replacement(node.end - 1, 1, "}" + (objectNeedsParens ? ")" : "")),
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];
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for (var i = 0; i < args.length; ++i) {
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var arg = args[i];
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if (tsutils_1.isObjectLiteralExpression(arg)) {
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if (arg.properties.length === 0) {
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var end = arg.end;
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if (i !== args.length - 1) {
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end = args[i + 1].getStart(sourceFile);
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}
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else if (args.hasTrailingComma) {
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end = args.end;
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}
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// remove empty object iteral and the following comma if exists
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fix.push(Lint.Replacement.deleteFromTo(arg.getStart(sourceFile), end));
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}
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else {
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fix.push(
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// remove open brace
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Lint.Replacement.deleteText(arg.getStart(sourceFile), 1),
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// remove trailing comma if exists and close brace
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Lint.Replacement.deleteFromTo(arg.properties[arg.properties.length - 1].end, arg.end));
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}
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}
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else {
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var parens = needsParens(arg);
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fix.push(Lint.Replacement.appendText(arg.getStart(sourceFile), parens ? "...(" : "..."));
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if (parens) {
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fix.push(Lint.Replacement.appendText(arg.end, ")"));
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}
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}
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}
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return fix;
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}
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function isThisKeyword(node) {
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return node.kind === ts.SyntaxKind.ThisKeyword;
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}
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function needsParens(node) {
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switch (node.kind) {
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case ts.SyntaxKind.ConditionalExpression:
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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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