"use strict";
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/**
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* @license
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* Copyright 2017 Palantir Technologies, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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Object.defineProperty(exports, "__esModule", { value: true });
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var tslib_1 = require("tslib");
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var tsutils_1 = require("tsutils");
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var ts = require("typescript");
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var Lint = require("../index");
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var Rule = /** @class */ (function (_super) {
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tslib_1.__extends(Rule, _super);
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function Rule() {
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return _super !== null && _super.apply(this, arguments) || this;
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}
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Rule.prototype.applyWithProgram = function (sourceFile, program) {
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return this.applyWithFunction(sourceFile, walk, undefined, program.getTypeChecker());
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};
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/* tslint:disable:object-literal-sort-keys */
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Rule.metadata = {
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ruleName: "return-undefined",
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description: "Prefer `return;` in void functions and `return undefined;` in value-returning functions.",
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optionsDescription: "Not configurable.",
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options: null,
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optionExamples: [true],
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type: "style",
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typescriptOnly: false,
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requiresTypeInfo: true,
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};
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/* tslint:enable:object-literal-sort-keys */
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Rule.FAILURE_STRING_VALUE_RETURN = "Value-returning function should use `return undefined;`, not just `return;`.";
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Rule.FAILURE_STRING_VOID_RETURN = "`void` function should use `return;`, not `return undefined;`.";
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return Rule;
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}(Lint.Rules.TypedRule));
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exports.Rule = Rule;
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function walk(ctx, checker) {
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return ts.forEachChild(ctx.sourceFile, function cb(node) {
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if (tsutils_1.isReturnStatement(node)) {
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check(node);
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}
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return ts.forEachChild(node, cb);
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});
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function check(node) {
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var actualReturnKind = returnKindFromReturn(node);
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if (actualReturnKind === undefined) {
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return;
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}
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var functionReturningFrom = Lint.ancestorWhere(node, isFunctionLike);
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if (functionReturningFrom === undefined) {
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// Return outside of function is invalid
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return;
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}
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var returnKindFromType = getReturnKind(functionReturningFrom, checker);
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if (returnKindFromType !== undefined && returnKindFromType !== actualReturnKind) {
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ctx.addFailureAtNode(node, returnKindFromType === ReturnKind.Void
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? Rule.FAILURE_STRING_VOID_RETURN
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: Rule.FAILURE_STRING_VALUE_RETURN);
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}
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}
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}
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function returnKindFromReturn(node) {
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if (node.expression === undefined) {
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return ReturnKind.Void;
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}
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else if (tsutils_1.isIdentifier(node.expression) && node.expression.text === "undefined") {
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return ReturnKind.Value;
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}
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else {
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return undefined;
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}
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}
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var ReturnKind;
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(function (ReturnKind) {
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ReturnKind[ReturnKind["Void"] = 0] = "Void";
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ReturnKind[ReturnKind["Value"] = 1] = "Value";
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})(ReturnKind || (ReturnKind = {}));
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function getReturnKind(node, checker) {
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switch (node.kind) {
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case ts.SyntaxKind.Constructor:
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case ts.SyntaxKind.SetAccessor:
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return ReturnKind.Void;
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case ts.SyntaxKind.GetAccessor:
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return ReturnKind.Value;
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}
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// Handle generator functions/methods:
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if (node.asteriskToken !== undefined) {
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return ReturnKind.Void;
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}
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var contextual = isFunctionExpressionLike(node) && node.type === undefined
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? tryGetReturnType(checker.getContextualType(node), checker)
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: undefined;
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var returnType = contextual !== undefined
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? contextual
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: tryGetReturnType(checker.getTypeAtLocation(node), checker);
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if (returnType === undefined || tsutils_1.isTypeFlagSet(returnType, ts.TypeFlags.Any)) {
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return undefined;
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}
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if ((tsutils_1.hasModifier(node.modifiers, ts.SyntaxKind.AsyncKeyword)
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? isEffectivelyVoidPromise
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: isEffectivelyVoid)(returnType)) {
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return ReturnKind.Void;
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}
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return ReturnKind.Value;
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}
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/** True for `void`, `undefined`, Promise<void>, or `void | undefined | Promise<void>`. */
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function isEffectivelyVoidPromise(type) {
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// Would need access to `checker.getPromisedTypeOfPromise` to do this properly.
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// Assume that the return type is the global Promise (since this is an async function) and get its type argument.
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return (
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// tslint:disable-next-line:no-bitwise
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tsutils_1.isTypeFlagSet(type, ts.TypeFlags.Void | ts.TypeFlags.Undefined) ||
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(tsutils_1.isUnionType(type) && type.types.every(isEffectivelyVoidPromise)) ||
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(tsutils_1.isTypeReference(type) &&
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type.typeArguments !== undefined &&
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type.typeArguments.length === 1 &&
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isEffectivelyVoidPromise(type.typeArguments[0])));
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}
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/** True for `void`, `undefined`, or `void | undefined`. */
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function isEffectivelyVoid(type) {
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return (
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// tslint:disable-next-line:no-bitwise
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tsutils_1.isTypeFlagSet(type, ts.TypeFlags.Void | ts.TypeFlags.Undefined) ||
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(tsutils_1.isUnionType(type) && type.types.every(isEffectivelyVoid)));
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}
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function tryGetReturnType(fnType, checker) {
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if (fnType === undefined) {
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return undefined;
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}
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var sigs = checker.getSignaturesOfType(fnType, ts.SignatureKind.Call);
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if (sigs.length !== 1) {
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return undefined;
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}
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return checker.getReturnTypeOfSignature(sigs[0]);
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}
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function isFunctionLike(node) {
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switch (node.kind) {
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case ts.SyntaxKind.FunctionDeclaration:
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case ts.SyntaxKind.FunctionExpression:
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case ts.SyntaxKind.ArrowFunction:
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case ts.SyntaxKind.MethodDeclaration:
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case ts.SyntaxKind.Constructor:
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case ts.SyntaxKind.GetAccessor:
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case ts.SyntaxKind.SetAccessor:
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return true;
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default:
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return false;
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}
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}
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function isFunctionExpressionLike(node) {
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return (node.kind === ts.SyntaxKind.FunctionExpression || node.kind === ts.SyntaxKind.ArrowFunction);
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}
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