Initial commit (from f5274cbdce4ae7c9e4b937dcdf95ac70ae436d5f)

node_modules/tslint/lib/rules/preferConditionalExpressionRule.js

@@ -0,0 +1,115 @@
+"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 tsutils_1 = require("tsutils");
+var ts = require("typescript");
+var Lint = require("../index");
+var OPTION_CHECK_ELSE_IF = "check-else-if";
+var Rule = /** @class */ (function (_super) {
+    tslib_1.__extends(Rule, _super);
+    function Rule() {
+        return _super !== null && _super.apply(this, arguments) || this;
+    }
+    /* tslint:enable:object-literal-sort-keys */
+    Rule.FAILURE_STRING = function (assigned) {
+        return "Use a conditional expression instead of assigning to '" + assigned + "' in multiple places.";
+    };
+    Rule.prototype.apply = function (sourceFile) {
+        return this.applyWithFunction(sourceFile, walk, {
+            checkElseIf: this.ruleArguments.indexOf(OPTION_CHECK_ELSE_IF) !== -1,
+        });
+    };
+    /* tslint:disable:object-literal-sort-keys */
+    Rule.metadata = {
+        ruleName: "prefer-conditional-expression",
+        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."]))),
+        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."]))),
+        optionsDescription: "If `" + OPTION_CHECK_ELSE_IF + "` is specified, the rule also checks nested if-else-if statements.",
+        options: {
+            type: "string",
+            enum: [OPTION_CHECK_ELSE_IF],
+        },
+        optionExamples: [true, [true, OPTION_CHECK_ELSE_IF]],
+        type: "functionality",
+        typescriptOnly: false,
+    };
+    return Rule;
+}(Lint.Rules.AbstractRule));
+exports.Rule = Rule;
+function walk(ctx) {
+    var sourceFile = ctx.sourceFile, checkElseIf = ctx.options.checkElseIf;
+    return ts.forEachChild(sourceFile, function cb(node) {
+        if (tsutils_1.isIfStatement(node)) {
+            var assigned = detectAssignment(node, sourceFile, checkElseIf);
+            if (assigned !== undefined) {
+                ctx.addFailureAtNode(node.getChildAt(0, sourceFile), Rule.FAILURE_STRING(assigned.getText(sourceFile)));
+            }
+            if (assigned !== undefined || !checkElseIf) {
+                // Be careful not to fail again for the "else if"
+                do {
+                    ts.forEachChild(node.expression, cb);
+                    ts.forEachChild(node.thenStatement, cb);
+                    if (node.elseStatement === undefined) {
+                        return;
+                    }
+                    node = node.elseStatement;
+                    while (tsutils_1.isBlock(node) && node.statements.length === 1) {
+                        node = node.statements[0];
+                    }
+                } while (tsutils_1.isIfStatement(node));
+            }
+        }
+        return ts.forEachChild(node, cb);
+    });
+}
+/**
+ * @param inElse `undefined` when this is the top level if statement, `false` when inside the then branch, `true` when inside else
+ */
+function detectAssignment(statement, sourceFile, checkElseIf, inElse) {
+    if (tsutils_1.isIfStatement(statement)) {
+        if (inElse === false || (!checkElseIf && inElse) || statement.elseStatement === undefined) {
+            return undefined;
+        }
+        var then = detectAssignment(statement.thenStatement, sourceFile, checkElseIf, false);
+        if (then === undefined) {
+            return undefined;
+        }
+        var elze = detectAssignment(statement.elseStatement, sourceFile, checkElseIf, true);
+        return elze !== undefined && nodeEquals(then, elze, sourceFile) ? then : undefined;
+    }
+    else if (tsutils_1.isBlock(statement)) {
+        return statement.statements.length === 1
+            ? detectAssignment(statement.statements[0], sourceFile, checkElseIf, inElse)
+            : undefined;
+    }
+    else if (tsutils_1.isExpressionStatement(statement) && tsutils_1.isBinaryExpression(statement.expression)) {
+        var _a = statement.expression, kind = _a.operatorToken.kind, left = _a.left, right = _a.right;
+        return kind === ts.SyntaxKind.EqualsToken &&
+            tsutils_1.isSameLine(sourceFile, right.getStart(sourceFile), right.end)
+            ? left
+            : undefined;
+    }
+    else {
+        return undefined;
+    }
+}
+function nodeEquals(a, b, sourceFile) {
+    return a.getText(sourceFile) === b.getText(sourceFile);
+}
+var templateObject_1, templateObject_2;