tslint
Version:
An extensible static analysis linter for the TypeScript language
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JavaScript
;
/**
* @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 });
exports.Rule = void 0;
var tslib_1 = require("tslib");
var utils = require("tsutils");
var ts = require("typescript");
var Lint = require("../index");
var utils_1 = require("../language/utils");
var arrowReturnShorthand_examples_1 = require("./code-examples/arrowReturnShorthand.examples");
var OPTION_MULTILINE = "multiline";
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 (isObjectLiteral) {
var start = "This arrow function body can be simplified by omitting the curly braces and the keyword 'return'";
return (start + (isObjectLiteral ? ", and wrapping the object literal in parentheses." : "."));
};
Rule.prototype.apply = function (sourceFile) {
return this.applyWithFunction(sourceFile, walk, {
multiline: this.ruleArguments.indexOf(OPTION_MULTILINE) !== -1,
});
};
/* tslint:disable:object-literal-sort-keys */
Rule.metadata = {
ruleName: "arrow-return-shorthand",
description: "Suggests to convert `() => { return x; }` to `() => x`.",
hasFix: true,
optionsDescription: Lint.Utils.dedent(templateObject_1 || (templateObject_1 = tslib_1.__makeTemplateObject(["\n If `", "` is specified, then this will warn even if the function spans multiple lines."], ["\n If \\`", "\\` is specified, then this will warn even if the function spans multiple lines."])), OPTION_MULTILINE),
options: {
type: "string",
enum: [OPTION_MULTILINE],
},
optionExamples: [true, [true, OPTION_MULTILINE]],
rationale: Lint.Utils.dedent(templateObject_2 || (templateObject_2 = tslib_1.__makeTemplateObject(["\n It's unnecessary to include `return` and `{}` brackets in arrow lambdas.\n Leaving them out results in simpler and easier to read code.\n "], ["\n It's unnecessary to include \\`return\\` and \\`{}\\` brackets in arrow lambdas.\n Leaving them out results in simpler and easier to read code.\n "]))),
type: "style",
typescriptOnly: false,
codeExamples: arrowReturnShorthand_examples_1.codeExamples,
};
return Rule;
}(Lint.Rules.AbstractRule));
exports.Rule = Rule;
function walk(ctx) {
var sourceFile = ctx.sourceFile, multiline = ctx.options.multiline;
return ts.forEachChild(sourceFile, function cb(node) {
if (utils.isArrowFunction(node) && utils.isBlock(node.body)) {
var expr = getSimpleReturnExpression(node.body);
if (expr !== undefined &&
(multiline ||
utils.isSameLine(sourceFile, node.body.getStart(sourceFile), node.body.end))) {
var isObjectLiteral = expr.kind === ts.SyntaxKind.ObjectLiteralExpression;
ctx.addFailureAtNode(node.body, Rule.FAILURE_STRING(isObjectLiteral), createFix(node, node.body, expr, sourceFile.text));
}
}
return ts.forEachChild(node, cb);
});
}
function createFix(arrowFunction, body, expr, text) {
var statement = expr.parent;
var returnKeyword = utils.getChildOfKind(statement, ts.SyntaxKind.ReturnKeyword);
var arrow = utils.getChildOfKind(arrowFunction, ts.SyntaxKind.EqualsGreaterThanToken);
var openBrace = utils.getChildOfKind(body, ts.SyntaxKind.OpenBraceToken);
var closeBrace = utils.getChildOfKind(body, ts.SyntaxKind.CloseBraceToken);
var semicolon = utils.getChildOfKind(statement, ts.SyntaxKind.SemicolonToken);
var anyComments = hasComments(arrow) ||
hasComments(openBrace) ||
hasComments(statement) ||
hasComments(returnKeyword) ||
hasComments(expr) ||
(semicolon !== undefined && hasComments(semicolon)) ||
hasComments(closeBrace);
return anyComments
? undefined
: tslib_1.__spreadArrays((expr.kind === ts.SyntaxKind.ObjectLiteralExpression
? [
Lint.Replacement.appendText(expr.getStart(), "("),
Lint.Replacement.appendText(expr.getEnd(), ")"),
]
: []), [
// " {"
Lint.Replacement.deleteFromTo(arrow.end, openBrace.end),
// "return "
Lint.Replacement.deleteFromTo(statement.getStart(), expr.getStart()),
// " }" (may include semicolon)
Lint.Replacement.deleteFromTo(expr.end, closeBrace.end),
]);
function hasComments(node) {
return utils_1.hasCommentAfterPosition(text, node.getEnd());
}
}
/** Given `{ return x; }`, return `x`. */
function getSimpleReturnExpression(block) {
return block.statements.length === 1 &&
block.statements[0].kind === ts.SyntaxKind.ReturnStatement
? block.statements[0].expression
: undefined;
}
var templateObject_1, templateObject_2;