97 lines
4.2 KiB
JavaScript
97 lines
4.2 KiB
JavaScript
|
"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 Rule = (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);
|
||
|
|
};
|
||
|
|
return Rule;
|
||
|
|
}(Lint.Rules.AbstractRule));
|
||
|
|
/* tslint:disable:object-literal-sort-keys */
|
||
|
|
Rule.metadata = {
|
||
|
|
ruleName: "prefer-conditional-expression",
|
||
|
|
description: (_a = ["\n Recommends to use a conditional expression instead of assigning to the same thing in each branch of an if statement."], _a.raw = ["\n Recommends to use a conditional expression instead of assigning to the same thing in each branch of an if statement."], Lint.Utils.dedent(_a)),
|
||
|
|
rationale: (_b = ["\n This reduces duplication and can eliminate an unnecessary variable declaration."], _b.raw = ["\n This reduces duplication and can eliminate an unnecessary variable declaration."], Lint.Utils.dedent(_b)),
|
||
|
|
optionsDescription: "Not configurable.",
|
||
|
|
options: null,
|
||
|
|
optionExamples: [true],
|
||
|
|
type: "functionality",
|
||
|
|
typescriptOnly: false,
|
||
|
|
};
|
||
|
|
exports.Rule = Rule;
|
||
|
|
function walk(ctx) {
|
||
|
|
var sourceFile = ctx.sourceFile;
|
||
|
|
return ts.forEachChild(sourceFile, function cb(node) {
|
||
|
|
if (tsutils_1.isIfStatement(node)) {
|
||
|
|
var assigned = detect(node, sourceFile);
|
||
|
|
if (assigned !== undefined) {
|
||
|
|
ctx.addFailureAtNode(Lint.childOfKind(node, ts.SyntaxKind.IfKeyword), Rule.FAILURE_STRING(assigned.getText(sourceFile)));
|
||
|
|
// Be careful not to fail again for the "else if"
|
||
|
|
ts.forEachChild(node.expression, cb);
|
||
|
|
ts.forEachChild(node.thenStatement, cb);
|
||
|
|
if (node.elseStatement !== undefined) {
|
||
|
|
ts.forEachChild(node.elseStatement, cb);
|
||
|
|
}
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return ts.forEachChild(node, cb);
|
||
|
|
});
|
||
|
|
}
|
||
|
|
function detect(_a, sourceFile) {
|
||
|
|
var thenStatement = _a.thenStatement, elseStatement = _a.elseStatement;
|
||
|
|
if (elseStatement === undefined) {
|
||
|
|
return undefined;
|
||
|
|
}
|
||
|
|
var elze = tsutils_1.isIfStatement(elseStatement) ? detect(elseStatement, sourceFile) : getAssigned(elseStatement, sourceFile);
|
||
|
|
if (elze === undefined) {
|
||
|
|
return undefined;
|
||
|
|
}
|
||
|
|
var then = getAssigned(thenStatement, sourceFile);
|
||
|
|
return then !== undefined && nodeEquals(elze, then, sourceFile) ? then : undefined;
|
||
|
|
}
|
||
|
|
/** Returns the left side of an assignment. */
|
||
|
|
function getAssigned(node, sourceFile) {
|
||
|
|
if (tsutils_1.isBlock(node)) {
|
||
|
|
return node.statements.length === 1 ? getAssigned(node.statements[0], sourceFile) : undefined;
|
||
|
|
}
|
||
|
|
else if (tsutils_1.isExpressionStatement(node) && tsutils_1.isBinaryExpression(node.expression)) {
|
||
|
|
var _a = node.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 _a, _b;
|