diff --git a/src/configs/all.ts b/src/configs/all.ts index 35631ae4e10..8c3a6ff35e5 100644 --- a/src/configs/all.ts +++ b/src/configs/all.ts @@ -18,7 +18,6 @@ import { join as joinPaths } from "path"; import { findRule } from "../ruleLoader"; -import { hasOwnProperty } from "../utils"; // tslint:disable object-literal-sort-keys // tslint:disable object-literal-key-quotes @@ -51,6 +50,7 @@ export const rules = { }, "no-any": true, "no-empty-interface": true, + "no-for-in": true, "no-import-side-effect": true, // Technically this is not the strictest setting, but don't want to conflict with "typedef" "no-inferrable-types": { options: ["ignore-params"] }, @@ -298,11 +298,7 @@ export const RULES_EXCLUDED_FROM_ALL_CONFIG = [ // Exclude typescript-only rules from jsRules, otherwise it's identical. export const jsRules: { [key: string]: any } = {}; -for (const key in rules) { - if (!hasOwnProperty(rules, key)) { - continue; - } - +for (const key of Object.keys(rules)) { const Rule = findRule(key, joinPaths(__dirname, "..", "rules")); if (Rule === undefined) { throw new Error(`Couldn't find rule '${key}'.`); diff --git a/src/configuration.ts b/src/configuration.ts index baf9d59bf0c..d5e3a60c873 100644 --- a/src/configuration.ts +++ b/src/configuration.ts @@ -24,7 +24,7 @@ import * as path from "path"; import { FatalError, showWarningOnce } from "./error"; import { IOptions, RuleSeverity } from "./language/rule/rule"; import { findRule } from "./ruleLoader"; -import { arrayify, hasOwnProperty, stripComments, tryResolvePackage } from "./utils"; +import { arrayify, stripComments, tryResolvePackage } from "./utils"; export interface IConfigurationFile { /** @@ -321,7 +321,10 @@ export function extendConfigurationFile( targetConfig: IConfigurationFile, nextConfigSource: IConfigurationFile, ): IConfigurationFile { - function combineProperties(targetProperty: T | undefined, nextProperty: T | undefined): T { + function combineProperties( + targetProperty: T | undefined, + nextProperty: T | undefined, + ): T { const combinedProperty: { [key: string]: any } = {}; add(targetProperty); // next config source overwrites the target config object @@ -330,10 +333,8 @@ export function extendConfigurationFile( function add(property: T | undefined): void { if (property !== undefined) { - for (const name in property) { - if (hasOwnProperty(property, name)) { - combinedProperty[name] = property[name]; - } + for (const name of Object.keys(property)) { + combinedProperty[name] = property[name]; } } } @@ -578,10 +579,8 @@ export function parseConfigFile( function parseRules(config: RawRulesConfig | undefined): Map> { const map = new Map>(); if (config !== undefined) { - for (const ruleName in config) { - if (hasOwnProperty(config, ruleName)) { - map.set(ruleName, parseRuleOptions(config[ruleName], defaultSeverity)); - } + for (const ruleName of Object.keys(config)) { + map.set(ruleName, parseRuleOptions(config[ruleName], defaultSeverity)); } } return map; diff --git a/src/rules/completed-docs/exclusions.ts b/src/rules/completed-docs/exclusions.ts index f575fa2df9c..e6746628174 100644 --- a/src/rules/completed-docs/exclusions.ts +++ b/src/rules/completed-docs/exclusions.ts @@ -15,7 +15,6 @@ * limitations under the License. */ -import { hasOwnProperty } from "../../utils"; import { DESCRIPTOR_OVERLOADS, DocType } from "../completedDocsRule"; import { BlockExclusion, IBlockExclusionDescriptor } from "./blockExclusion"; @@ -49,13 +48,11 @@ const addRequirements = (exclusionsMap: ExclusionsMap, descriptors: IInputExclus return; } - for (const docType in descriptors) { - if (hasOwnProperty(descriptors, docType)) { - exclusionsMap.set( - docType as DocType, - createRequirementsForDocType(docType as DocType, descriptors[docType]), - ); - } + for (const docType of Object.keys(descriptors)) { + exclusionsMap.set( + docType as DocType, + createRequirementsForDocType(docType as DocType, descriptors[docType]), + ); } }; diff --git a/src/rules/noForInRule.ts b/src/rules/noForInRule.ts new file mode 100644 index 00000000000..4a485c45b55 --- /dev/null +++ b/src/rules/noForInRule.ts @@ -0,0 +1,55 @@ +/** + * @license + * Copyright 2019 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. + */ + +import { isForInStatement } from "tsutils"; +import * as ts from "typescript"; + +import * as Lint from "../index"; + +export class Rule extends Lint.Rules.AbstractRule { + public static metadata: Lint.IRuleMetadata = { + description: "Ban the usage of for...in statements.", + optionExamples: [true], + options: null, + optionsDescription: "Not configurable.", + rationale: + "for...in statements are legacy JavaScript syntax which usually require a verbose `hasOwnProperty` check inside their loop body. These statements can be fully replaced with for...of statements in modern JS & TS.", + ruleName: "no-for-in", + type: "typescript", + typescriptOnly: false, + }; + + public static FAILURE_STRING_FACTORY(): string { + return `Use a for...of statement instead of for...in. If iterating over an object, use Object.keys() to access its enumerable keys.`; + } + + public apply(sourceFile: ts.SourceFile): Lint.RuleFailure[] { + return this.applyWithFunction(sourceFile, walk); + } +} + +function walk(ctx: Lint.WalkContext) { + function cb(node: ts.Node): void { + if (isForInStatement(node)) { + const msg: string = Rule.FAILURE_STRING_FACTORY(); + ctx.addFailureAt(node.getStart(), node.getWidth(), msg); + } + return ts.forEachChild(node, cb); + } + + return ts.forEachChild(ctx.sourceFile, cb); +} diff --git a/src/rules/noImplicitDependenciesRule.ts b/src/rules/noImplicitDependenciesRule.ts index 681f910365f..1a124dddf17 100644 --- a/src/rules/noImplicitDependenciesRule.ts +++ b/src/rules/noImplicitDependenciesRule.ts @@ -165,10 +165,8 @@ function getDependencies(fileName: string, options: Options): Set { } function addDependencies(result: Set, dependencies: Dependencies) { - for (const name in dependencies) { - if (dependencies.hasOwnProperty(name)) { - result.add(name); - } + for (const name of Object.keys(dependencies)) { + result.add(name); } } diff --git a/test/rules/no-for-in/test.ts.lint b/test/rules/no-for-in/test.ts.lint new file mode 100644 index 00000000000..a3dd806a466 --- /dev/null +++ b/test/rules/no-for-in/test.ts.lint @@ -0,0 +1,20 @@ +const columns = [{ data: [1] }]; +for (let i = 0; i < columns[0].data.length; i++) { + columns.map((x) => x.data[i]); +} + +const object = { test: 1, test2: 1, test3: 1 }; +for (const key in object) { +~~~~~~~~~~~~~~~~~~~~~~~~~~~ + if (object.hasOwnProperty(key)) { +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + const element = object[key]; +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + } +~~ +} +~ [Use a for...of statement instead of for...in. If iterating over an object, use Object.keys() to access its enumerable keys.] + +for (const key of Object.keys(object)) { + const value = object[key]; +} diff --git a/test/rules/no-for-in/tslint.json b/test/rules/no-for-in/tslint.json new file mode 100644 index 00000000000..2a62503d3e3 --- /dev/null +++ b/test/rules/no-for-in/tslint.json @@ -0,0 +1,5 @@ +{ + "rules": { + "no-for-in": true + } +}