--- /dev/null
+"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 _a, _b;
+var utils = require("tsutils");
+var ts = require("typescript");
+var Lint = require("../index");
+var OPTION_MIN_CASES = "min-cases";
+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) {
+ var minCases = 3;
+ if (this.ruleArguments.length !== 0) {
+ var obj = this.ruleArguments[0];
+ minCases = obj[OPTION_MIN_CASES];
+ }
+ return this.applyWithFunction(sourceFile, walk, minCases);
+ };
+ /* tslint:disable:object-literal-sort-keys */
+ Rule.metadata = {
+ ruleName: "prefer-switch",
+ description: "Prefer a `switch` statement to an `if` statement with simple `===` comparisons.",
+ optionsDescription: Lint.Utils.dedent(templateObject_1 || (templateObject_1 = tslib_1.__makeTemplateObject(["\n An optional object with the property '", "'.\n This is the number cases needed before a switch statement is recommended.\n Defaults to 3."], ["\n An optional object with the property '", "'.\n This is the number cases needed before a switch statement is recommended.\n Defaults to 3."])), OPTION_MIN_CASES),
+ options: {
+ type: "object",
+ properties: (_a = {},
+ _a[OPTION_MIN_CASES] = { type: "number" },
+ _a),
+ },
+ optionExamples: [true, [true, (_b = {}, _b[OPTION_MIN_CASES] = 2, _b)]],
+ type: "style",
+ typescriptOnly: false,
+ };
+ /* tslint:enable:object-literal-sort-keys */
+ Rule.FAILURE_STRING = "Use a switch statement instead of using multiple '===' checks.";
+ return Rule;
+}(Lint.Rules.AbstractRule));
+exports.Rule = Rule;
+function walk(ctx) {
+ var minCases = ctx.options, sourceFile = ctx.sourceFile;
+ return ts.forEachChild(sourceFile, function cb(node) {
+ if (utils.isIfStatement(node) && check(node, sourceFile, minCases)) {
+ var expression = node.expression, thenStatement = node.thenStatement, elseStatement = node.elseStatement;
+ ctx.addFailureAtNode(expression, Rule.FAILURE_STRING);
+ // Be careful not to fail again for the "else if"
+ ts.forEachChild(expression, cb);
+ ts.forEachChild(thenStatement, cb);
+ if (elseStatement !== undefined) {
+ ts.forEachChild(elseStatement, cb);
+ }
+ }
+ else {
+ return ts.forEachChild(node, cb);
+ }
+ });
+}
+function check(node, sourceFile, minCases) {
+ var switchVariable;
+ var casesSeen = 0;
+ var couldBeSwitch = everyCase(node, function (expr) {
+ casesSeen++;
+ if (switchVariable !== undefined) {
+ return nodeEquals(expr, switchVariable, sourceFile);
+ }
+ else {
+ switchVariable = expr;
+ return true;
+ }
+ });
+ return couldBeSwitch && casesSeen >= minCases;
+}
+function everyCase(_a, test) {
+ var expression = _a.expression, elseStatement = _a.elseStatement;
+ if (!everyCondition(expression, test)) {
+ return false;
+ }
+ return (elseStatement === undefined ||
+ !utils.isIfStatement(elseStatement) ||
+ everyCase(elseStatement, test));
+}
+function everyCondition(node, test) {
+ if (!utils.isBinaryExpression(node)) {
+ return false;
+ }
+ var operatorToken = node.operatorToken, left = node.left, right = node.right;
+ switch (operatorToken.kind) {
+ case ts.SyntaxKind.BarBarToken:
+ return everyCondition(left, test) && everyCondition(right, test);
+ case ts.SyntaxKind.EqualsEqualsEqualsToken:
+ return isSimple(left) && isSimple(right) && test(left);
+ default:
+ return false;
+ }
+}
+function nodeEquals(a, b, sourceFile) {
+ return a.getText(sourceFile) === b.getText(sourceFile);
+}
+function isSimple(node) {
+ switch (node.kind) {
+ case ts.SyntaxKind.PropertyAccessExpression:
+ return isSimple(node.expression);
+ case ts.SyntaxKind.PrefixUnaryExpression:
+ switch (node.operator) {
+ case ts.SyntaxKind.PlusPlusToken:
+ case ts.SyntaxKind.MinusMinusToken:
+ return false;
+ default:
+ return isSimple(node.operand);
+ }
+ case ts.SyntaxKind.Identifier:
+ case ts.SyntaxKind.NumericLiteral:
+ case ts.SyntaxKind.StringLiteral:
+ case ts.SyntaxKind.ThisKeyword:
+ case ts.SyntaxKind.NoSubstitutionTemplateLiteral:
+ case ts.SyntaxKind.TrueKeyword:
+ case ts.SyntaxKind.FalseKeyword:
+ case ts.SyntaxKind.NullKeyword:
+ return true;
+ default:
+ return false;
+ }
+}
+var templateObject_1;