"use strict"; /** * @license * Copyright 2018 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 tsutils_1 = require("tsutils"); var ts = require("typescript"); var Lint = require("../index"); var OPTION_IGNORE_ARROW_FUNCTION_SHORTHAND = "ignore-arrow-function-shorthand"; var Rule = /** @class */ (function (_super) { tslib_1.__extends(Rule, _super); function Rule() { return _super !== null && _super.apply(this, arguments) || this; } Rule.prototype.applyWithProgram = function (sourceFile, program) { var ignoreArrowFunctionShorthand = this.ruleArguments.indexOf(OPTION_IGNORE_ARROW_FUNCTION_SHORTHAND) !== -1; return this.applyWithFunction(sourceFile, walk, { ignoreArrowFunctionShorthand: ignoreArrowFunctionShorthand }, program.getTypeChecker()); }; /* tslint:disable:object-literal-sort-keys */ Rule.metadata = { ruleName: "no-void-expression", description: "Requires expressions of type `void` to appear in statement position.", optionsDescription: Lint.Utils.dedent(templateObject_1 || (templateObject_1 = tslib_1.__makeTemplateObject(["\n If `", "` is provided, `() => returnsVoid()` will be allowed.\n Otherwise, it must be written as `() => { returnsVoid(); }`."], ["\n If \\`", "\\` is provided, \\`() => returnsVoid()\\` will be allowed.\n Otherwise, it must be written as \\`() => { returnsVoid(); }\\`."])), OPTION_IGNORE_ARROW_FUNCTION_SHORTHAND), options: { type: "array", items: { type: "string", enum: [OPTION_IGNORE_ARROW_FUNCTION_SHORTHAND], }, minLength: 0, maxLength: 1, }, rationale: Lint.Utils.dedent(templateObject_2 || (templateObject_2 = tslib_1.__makeTemplateObject(["\n It's misleading returning the results of an expression whose type is `void`.\n Attempting to do so is likely a symptom of expecting a different return type from a function.\n For example, the following code will log `undefined` but looks like it logs a value:\n\n ```\n const performWork = (): void => {\n workFirst();\n workSecond();\n };\n\n console.log(performWork());\n ```\n "], ["\n It's misleading returning the results of an expression whose type is \\`void\\`.\n Attempting to do so is likely a symptom of expecting a different return type from a function.\n For example, the following code will log \\`undefined\\` but looks like it logs a value:\n\n \\`\\`\\`\n const performWork = (): void => {\n workFirst();\n workSecond();\n };\n\n console.log(performWork());\n \\`\\`\\`\n "]))), requiresTypeInfo: true, type: "functionality", typescriptOnly: false, }; /* tslint:enable:object-literal-sort-keys */ Rule.FAILURE_STRING = "Expression has type `void`. Put it on its own line as a statement."; return Rule; }(Lint.Rules.TypedRule)); exports.Rule = Rule; function walk(ctx, checker) { var sourceFile = ctx.sourceFile, ignoreArrowFunctionShorthand = ctx.options.ignoreArrowFunctionShorthand; return ts.forEachChild(sourceFile, function cb(node) { if (isPossiblyVoidExpression(node) && !isParentAllowedVoid(node) && tsutils_1.isTypeFlagSet(checker.getTypeAtLocation(node), ts.TypeFlags.Void)) { ctx.addFailureAtNode(node, Rule.FAILURE_STRING); } return ts.forEachChild(node, cb); }); function isParentAllowedVoid(node) { switch (node.parent.kind) { case ts.SyntaxKind.ExpressionStatement: return true; case ts.SyntaxKind.ArrowFunction: return ignoreArrowFunctionShorthand; // Something like "x && console.log(x)". case ts.SyntaxKind.BinaryExpression: return isParentAllowedVoid(node.parent); // Something like "!!cond ? console.log(true) : console.log(false)" case ts.SyntaxKind.ConditionalExpression: return true; default: return false; } } } function isPossiblyVoidExpression(node) { switch (node.kind) { case ts.SyntaxKind.AwaitExpression: case ts.SyntaxKind.CallExpression: case ts.SyntaxKind.TaggedTemplateExpression: return true; default: return false; } } var templateObject_1, templateObject_2;