311 lines
15 KiB
JavaScript
311 lines
15 KiB
JavaScript
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"use strict";
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/**
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* @license
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* Copyright 2013 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 ts = require("typescript");
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var Lint = require("../index");
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var utils = require("tsutils");
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var OPTION_DESTRUCTURING_ALL = "all";
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var OPTION_DESTRUCTURING_ANY = "any";
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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_FACTORY = function (identifier, blockScoped) {
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return "Identifier '" + identifier + "' is never reassigned; use 'const' instead of '" + (blockScoped ? "let" : "var") + "'.";
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};
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Rule.prototype.apply = function (sourceFile) {
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var options = {
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destructuringAll: this.ruleArguments.length !== 0 &&
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this.ruleArguments[0].destructuring === OPTION_DESTRUCTURING_ALL,
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};
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var preferConstWalker = new PreferConstWalker(sourceFile, this.ruleName, options);
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return this.applyWithWalker(preferConstWalker);
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};
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return Rule;
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}(Lint.Rules.AbstractRule));
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/* tslint:disable:object-literal-sort-keys */
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Rule.metadata = {
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ruleName: "prefer-const",
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description: "Requires that variable declarations use `const` instead of `let` and `var` if possible.",
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descriptionDetails: (_a = ["\n If a variable is only assigned to once when it is declared, it should be declared using 'const'"], _a.raw = ["\n If a variable is only assigned to once when it is declared, it should be declared using 'const'"], Lint.Utils.dedent(_a)),
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hasFix: true,
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optionsDescription: (_b = ["\n An optional object containing the property \"destructuring\" with two possible values:\n\n * \"", "\" (default) - If any variable in destructuring can be const, this rule warns for those variables.\n * \"", "\" - Only warns if all variables in destructuring can be const."], _b.raw = ["\n An optional object containing the property \"destructuring\" with two possible values:\n\n * \"", "\" (default) - If any variable in destructuring can be const, this rule warns for those variables.\n * \"", "\" - Only warns if all variables in destructuring can be const."], Lint.Utils.dedent(_b, OPTION_DESTRUCTURING_ANY, OPTION_DESTRUCTURING_ALL)),
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options: {
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type: "object",
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properties: {
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destructuring: {
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type: "string",
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enum: [OPTION_DESTRUCTURING_ALL, OPTION_DESTRUCTURING_ANY],
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},
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},
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},
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optionExamples: [
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true,
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[true, { destructuring: OPTION_DESTRUCTURING_ALL }],
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],
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type: "maintainability",
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typescriptOnly: false,
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};
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exports.Rule = Rule;
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var Scope = (function () {
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function Scope(functionScope) {
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this.variables = new Map();
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this.reassigned = new Set();
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// if no functionScope is provided we are in the process of creating a new function scope, which for consistency links to itself
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this.functionScope = functionScope === undefined ? this : functionScope;
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}
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Scope.prototype.addVariable = function (identifier, declarationInfo, destructuringInfo) {
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// block scoped variables go to the block scope, function scoped variables to the containing function scope
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var scope = declarationInfo.isBlockScoped ? this : this.functionScope;
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scope.variables.set(identifier.text, {
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declarationInfo: declarationInfo,
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destructuringInfo: destructuringInfo,
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identifier: identifier,
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reassigned: false,
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});
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};
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return Scope;
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}());
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var PreferConstWalker = (function (_super) {
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tslib_1.__extends(PreferConstWalker, _super);
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function PreferConstWalker() {
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return _super !== null && _super.apply(this, arguments) || this;
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}
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PreferConstWalker.prototype.walk = function (sourceFile) {
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var _this = this;
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// don't check anything on declaration files
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if (sourceFile.isDeclarationFile) {
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return;
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}
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this.scope = new Scope();
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var cb = function (node) {
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var savedScope = _this.scope;
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var boundary = utils.isScopeBoundary(node);
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if (boundary !== 0 /* None */) {
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if (boundary === 1 /* Function */) {
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if (node.kind === ts.SyntaxKind.ModuleDeclaration && utils.hasModifier(node.modifiers, ts.SyntaxKind.DeclareKeyword)) {
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// don't check ambient namespaces
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return;
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}
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_this.scope = new Scope();
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if (utils.isFunctionDeclaration(node) ||
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utils.isMethodDeclaration(node) ||
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utils.isFunctionExpression(node) ||
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utils.isArrowFunction(node) ||
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utils.isConstructorDeclaration(node)) {
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// special handling for function parameters
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// each parameter initializer can only reassign preceding parameters of variables of the containing scope
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if (node.body !== undefined) {
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for (var _i = 0, _a = node.parameters; _i < _a.length; _i++) {
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var param = _a[_i];
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cb(param);
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_this.settle(savedScope);
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}
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cb(node.body);
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_this.onScopeEnd(savedScope);
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}
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_this.scope = savedScope;
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return;
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}
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}
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else {
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_this.scope = new Scope(_this.scope.functionScope);
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if ((utils.isForInStatement(node) || utils.isForOfStatement(node)) &&
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node.initializer.kind !== ts.SyntaxKind.VariableDeclarationList) {
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_this.handleExpression(node.initializer);
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}
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}
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}
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if (node.kind === ts.SyntaxKind.VariableDeclarationList) {
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_this.handleVariableDeclaration(node);
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}
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else if (node.kind === ts.SyntaxKind.CatchClause) {
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_this.handleBindingName(node.variableDeclaration.name, {
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canBeConst: false,
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isBlockScoped: true,
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});
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}
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else if (node.kind === ts.SyntaxKind.Parameter) {
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_this.handleBindingName(node.name, {
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canBeConst: false,
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isBlockScoped: true,
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});
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}
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else if (utils.isPostfixUnaryExpression(node) ||
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utils.isPrefixUnaryExpression(node) &&
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(node.operator === ts.SyntaxKind.PlusPlusToken || node.operator === ts.SyntaxKind.MinusMinusToken)) {
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if (utils.isIdentifier(node.operand)) {
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_this.scope.reassigned.add(node.operand.text);
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}
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}
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else if (utils.isBinaryExpression(node) && utils.isAssignmentKind(node.operatorToken.kind)) {
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_this.handleExpression(node.left);
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}
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if (boundary !== 0 /* None */) {
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ts.forEachChild(node, cb);
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_this.onScopeEnd(savedScope);
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_this.scope = savedScope;
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}
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else {
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return ts.forEachChild(node, cb);
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}
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};
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if (ts.isExternalModule(sourceFile)) {
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ts.forEachChild(sourceFile, cb);
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this.onScopeEnd();
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}
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else {
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return ts.forEachChild(sourceFile, cb);
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}
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};
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PreferConstWalker.prototype.handleExpression = function (node) {
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switch (node.kind) {
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case ts.SyntaxKind.Identifier:
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this.scope.reassigned.add(node.text);
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break;
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case ts.SyntaxKind.ParenthesizedExpression:
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this.handleExpression(node.expression);
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break;
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case ts.SyntaxKind.ArrayLiteralExpression:
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for (var _i = 0, _a = node.elements; _i < _a.length; _i++) {
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var element = _a[_i];
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if (element.kind === ts.SyntaxKind.SpreadElement) {
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this.handleExpression(element.expression);
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}
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else {
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this.handleExpression(element);
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}
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}
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break;
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case ts.SyntaxKind.ObjectLiteralExpression:
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for (var _b = 0, _c = node.properties; _b < _c.length; _b++) {
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var property = _c[_b];
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switch (property.kind) {
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case ts.SyntaxKind.ShorthandPropertyAssignment:
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this.scope.reassigned.add(property.name.text);
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break;
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case ts.SyntaxKind.SpreadAssignment:
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if (property.name !== undefined) {
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this.scope.reassigned.add(property.name.text);
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}
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else {
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// handle `...(variable)`
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this.handleExpression(property.expression);
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}
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break;
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default:
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this.handleExpression(property.initializer);
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}
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}
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break;
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}
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};
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PreferConstWalker.prototype.handleBindingName = function (name, declarationInfo) {
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var _this = this;
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if (name.kind === ts.SyntaxKind.Identifier) {
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this.scope.addVariable(name, declarationInfo);
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}
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else {
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var destructuringInfo_1 = {
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reassignedSiblings: false,
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};
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utils.forEachDestructuringIdentifier(name, function (declaration) { return _this.scope.addVariable(declaration.name, declarationInfo, destructuringInfo_1); });
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}
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};
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PreferConstWalker.prototype.handleVariableDeclaration = function (declarationList) {
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var declarationInfo;
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var kind = utils.getVariableDeclarationKind(declarationList);
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if (kind === 2 /* Const */ ||
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utils.hasModifier(declarationList.parent.modifiers, ts.SyntaxKind.ExportKeyword, ts.SyntaxKind.DeclareKeyword)) {
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declarationInfo = {
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canBeConst: false,
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isBlockScoped: kind !== 0 /* Var */,
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};
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}
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else {
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declarationInfo = {
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allInitialized: declarationList.parent.kind === ts.SyntaxKind.ForOfStatement ||
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declarationList.parent.kind === ts.SyntaxKind.ForInStatement ||
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declarationList.declarations.every(function (declaration) { return declaration.initializer !== undefined; }),
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canBeConst: true,
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declarationList: declarationList,
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isBlockScoped: kind === 1 /* Let */,
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isForLoop: declarationList.parent.kind === ts.SyntaxKind.ForStatement,
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reassignedSiblings: false,
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};
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}
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for (var _i = 0, _a = declarationList.declarations; _i < _a.length; _i++) {
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var declaration = _a[_i];
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this.handleBindingName(declaration.name, declarationInfo);
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}
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};
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PreferConstWalker.prototype.settle = function (parent) {
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var _a = this.scope, variables = _a.variables, reassigned = _a.reassigned;
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reassigned.forEach(function (name) {
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var variableInfo = variables.get(name);
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if (variableInfo !== undefined) {
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if (variableInfo.declarationInfo.canBeConst) {
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variableInfo.reassigned = true;
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variableInfo.declarationInfo.reassignedSiblings = true;
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if (variableInfo.destructuringInfo !== undefined) {
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variableInfo.destructuringInfo.reassignedSiblings = true;
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}
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}
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}
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else if (parent !== undefined) {
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// if the reassigned variable was not declared in this scope we defer to the parent scope
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parent.reassigned.add(name);
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}
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});
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reassigned.clear();
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};
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PreferConstWalker.prototype.onScopeEnd = function (parent) {
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var _this = this;
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this.settle(parent);
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var appliedFixes = new Set();
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this.scope.variables.forEach(function (info, name) {
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if (info.declarationInfo.canBeConst &&
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!info.reassigned &&
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// don't add failures for reassigned variables in for loop initializer
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!(info.declarationInfo.reassignedSiblings && info.declarationInfo.isForLoop) &&
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// if {destructuring: "all"} is set, only add a failure if all variables in a destructuring assignment can be const
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(!_this.options.destructuringAll ||
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info.destructuringInfo === undefined ||
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!info.destructuringInfo.reassignedSiblings)) {
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var fix = void 0;
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// only apply fixes if the VariableDeclarationList has no reassigned variables
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// and the variable is block scoped aka `let` and initialized
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if (info.declarationInfo.allInitialized &&
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!info.declarationInfo.reassignedSiblings &&
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info.declarationInfo.isBlockScoped &&
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!appliedFixes.has(info.declarationInfo.declarationList)) {
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fix = new Lint.Replacement(info.declarationInfo.declarationList.getStart(_this.sourceFile), 3, "const");
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// add only one fixer per VariableDeclarationList
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appliedFixes.add(info.declarationInfo.declarationList);
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}
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_this.addFailureAtNode(info.identifier, Rule.FAILURE_STRING_FACTORY(name, info.declarationInfo.isBlockScoped), fix);
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}
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});
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};
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return PreferConstWalker;
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}(Lint.AbstractWalker));
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var _a, _b;
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