migrate from tslint to eslint (#1120)

* migrate from tslint to eslint

* unignore .eslintrc.js

.eslintignore

@@ -0,0 +1,3 @@
+/.test/**
+/dist/**
+/test/**

.eslintrc.js

@@ -0,0 +1,37 @@
+module.exports = {
+  root: true,
+  parser: '@typescript-eslint/parser',
+  extends: ['plugin:node/recommended', 'plugin:prettier/recommended'],
+  parserOptions: {
+    ecmaVersion: 2018,
+    sourceType: 'module',
+  },
+  settings: {
+    node: {
+      tryExtensions: ['.js', '.json', '.ts', '.d.ts'],
+    },
+  },
+  rules: {
+    // 'no-process-exit': 'off', // to investigate if we should throw an error instead of process.exit()
+    // 'node/no-unsupported-features/es-builtins': 'off',
+  },
+  overrides: [
+    {
+      files: ['*.ts'],
+      extends: [
+        'plugin:@typescript-eslint/recommended', // Uses the recommended rules from the @typescript-eslint/eslint-plugin
+        'prettier/@typescript-eslint', // Uses eslint-config-prettier to disable ESLint rules from @typescript-eslint/eslint-plugin that would conflict with prettier
+        'plugin:prettier/recommended', // Enables eslint-plugin-prettier and eslint-config-prettier. This will display prettier errors as ESLint errors. Make sure this is always the last configuration in the extends array.
+      ],
+      rules: {
+        'node/no-unsupported-features/es-syntax': 'off',
+        '@typescript-eslint/explicit-module-boundary-types': 'off',
+        '@typescript-eslint/no-non-null-assertion': 'off',
+        '@typescript-eslint/no-explicit-any': 'off',
+        '@typescript-eslint/no-unused-vars': 'off',
+        // '@typescript-eslint/explicit-function-return-type': 'off',
+        // '@typescript-eslint/no-namespace': 'off' // maybe we should consider enabling it in the future
+      },
+    },
+  ],
+};

.gitignore

@@ -16,4 +16,5 @@ npm-debug.log
 !build.js
 /**/debug.log
 .pnp
-.pnp.js
+.pnp.js
+!.eslintrc.js

.prettierignore

@@ -0,0 +1 @@
+/test/**

.prettierrc

@@ -0,0 +1,8 @@
+{
+    "arrowParens": "avoid",
+    "singleQuote": true,
+    "semi": true,
+    "tabWidth": 2,
+    "useTabs": false,
+    "printWidth": 80
+}

package.json

@@ -6,7 +6,7 @@
   "types": "dist",
   "scripts": {
     "build": "tsc --version && tsc --project \"./src\"",
-    "lint": "tslint --project \"./src\"",
+    "lint": "eslint -c .eslintrc.js --ext .ts ./src",
     "comparison-tests": "git clean -xfd test/comparison-tests && npm link ./test/comparison-tests/testLib && node test/comparison-tests/run-tests.js",
     "comparison-tests-generate": "git clean -xfd test/comparison-tests && node test/comparison-tests/stub-new-version.js",
     "execution-tests": "git clean -xfd test/execution-tests && node test/execution-tests/run-tests.js",
@@ -24,6 +24,7 @@
   "lint-staged": {
     "src/**/*.{ts,md}": [
       "prettier --write",
+      "yarn lint",
       "git add"
     ]
   },
@@ -64,6 +65,8 @@
     "@types/node": "*",
     "@types/semver": "^6.0.0",
     "@types/webpack": "^4.4.30",
+    "@typescript-eslint/eslint-plugin": "^3.0.0",
+    "@typescript-eslint/parser": "^3.0.0",
     "babel": "^6.0.0",
     "babel-core": "^6.0.0",
     "babel-loader": "^7.0.0",
@@ -72,6 +75,10 @@
     "babel-preset-es2016": "^6.16.0",
     "babel-preset-react": "^6.0.0",
     "escape-string-regexp": "^2.0.0",
+    "eslint": "^7.1.0",
+    "eslint-config-prettier": "^6.11.0",
+    "eslint-plugin-node": "^11.1.0",
+    "eslint-plugin-prettier": "^3.1.3",
     "fs-extra": "^7.0.0",
     "glob": "^7.1.1",
     "html-webpack-plugin": "^3.2.0",
@@ -87,10 +94,8 @@
     "markdown-toc": "^1.2.0",
     "mkdirp": "^0.5.1",
     "mocha": "^6.0.0",
-    "prettier": "^1.11.1",
+    "prettier": "^2.0.5",
     "rimraf": "^2.6.2",
-    "tslint": "^5.11.0",
-    "tslint-config-prettier": "^1.15.0",
     "typescript": "^3.6.2",
     "webpack": "^4.5.0",
     "webpack-cli": "^3.1.1"

src/after-compile.ts

@@ -6,20 +6,20 @@ import * as constants from './constants';
 import {
   getEmitFromWatchHost,
   getEmitOutput,
-  isReferencedFile
+  isReferencedFile,
 } from './instances';
 import {
   TSFile,
   TSFiles,
   TSInstance,
   WebpackError,
-  WebpackModule
+  WebpackModule,
 } from './interfaces';
 import {
   collectAllDependants,
   ensureProgram,
   formatErrors,
-  isUsingProjectReferences
+  isUsingProjectReferences,
 } from './utils';
 
 export function makeAfterCompile(
@@ -190,7 +190,7 @@ function provideErrorsToWebpack(
     files,
     loaderOptions,
     compilerOptions,
-    otherFiles
+    otherFiles,
   } = instance;
 
   const filePathRegex =
@@ -284,7 +284,7 @@ function provideSolutionErrorsToWebpack(
   const {
     compiler,
     loaderOptions,
-    solutionBuilderHost: { diagnostics }
+    solutionBuilderHost: { diagnostics },
   } = instance;
 
   for (const [filePath, perFileDiagnostics] of diagnostics.perFile) {
@@ -380,7 +380,7 @@ function outputFileToAsset(
   );
   compilation.assets[assetPath] = {
     source: () => outputFile.text,
-    size: () => outputFile.text.length
+    size: () => outputFile.text.length,
   };
 }
 

src/compilerSetup.ts

@@ -16,9 +16,7 @@ export function getCompiler(loaderOptions: LoaderOptions, log: logger.Logger) {
     errorMessage =
       loaderOptions.compiler === 'typescript'
         ? 'Could not load TypeScript. Try installing with `yarn add typescript` or `npm install typescript`. If TypeScript is installed globally, try using `yarn link typescript` or `npm link typescript`.'
-        : `Could not load TypeScript compiler with NPM package name \`${
-            loaderOptions.compiler
-          }\`. Are you sure it is correctly installed?`;
+        : `Could not load TypeScript compiler with NPM package name \`${loaderOptions.compiler}\`. Are you sure it is correctly installed?`;
   }
 
   if (errorMessage === undefined) {
@@ -49,7 +47,7 @@ export function getCompiler(loaderOptions: LoaderOptions, log: logger.Logger) {
     compiler,
     compilerCompatible,
     compilerDetailsLogMessage,
-    errorMessage
+    errorMessage,
   };
 }
 
@@ -58,14 +56,14 @@ export function getCompilerOptions(
 ) {
   const compilerOptions = Object.assign({}, configParseResult.options, {
     skipLibCheck: true,
-    suppressOutputPathCheck: true // This is why: https://github.com/Microsoft/TypeScript/issues/7363
+    suppressOutputPathCheck: true, // This is why: https://github.com/Microsoft/TypeScript/issues/7363
   } as typescript.CompilerOptions);
 
   // if `module` is not specified and not using ES6+ target, default to CJS module output
   if (
     compilerOptions.module === undefined &&
-    (compilerOptions.target !== undefined &&
-      compilerOptions.target < typescript.ScriptTarget.ES2015)
+    compilerOptions.target !== undefined &&
+    compilerOptions.target < typescript.ScriptTarget.ES2015
   ) {
     compilerOptions.module = typescript.ModuleKind.CommonJS;
   }
@@ -74,7 +72,7 @@ export function getCompilerOptions(
     Object.defineProperty(compilerOptions, 'configFile', {
       enumerable: false,
       writable: false,
-      value: configParseResult.options.configFile
+      value: configParseResult.options.configFile,
     });
   }
 

src/config.ts

@@ -58,8 +58,8 @@ export function getConfigFile(
     configFile = {
       config: {
         compilerOptions: {},
-        files: []
-      }
+        files: [],
+      },
     };
   }
 
@@ -74,7 +74,7 @@ export function getConfigFile(
   return {
     configFilePath,
     configFile,
-    configFileError
+    configFileError,
   };
 }
 
@@ -144,7 +144,7 @@ export function getConfigParseResult(
   if (semver.gte(compiler.version, '3.5.0')) {
     // set internal options.configFilePath flag on options to denote that we read this from a file
     configParseResult.options = Object.assign({}, configParseResult.options, {
-      configFilePath
+      configFilePath,
     });
   }
 
@@ -164,7 +164,8 @@ export function getParsedCommandLine(
     loaderOptions.compilerOptions,
     {
       ...compiler.sys,
-      onUnRecoverableConfigFileDiagnostic: () => {} // tslint:disable-line no-empty
+      // eslint-disable-next-line @typescript-eslint/no-empty-function
+      onUnRecoverableConfigFileDiagnostic: () => {},
     },
     extendedConfigCache
   );

src/index.ts

@@ -12,22 +12,22 @@ import {
   getTypeScriptInstance,
   initializeInstance,
   isReferencedFile,
-  reportTranspileErrors
+  reportTranspileErrors,
 } from './instances';
 import {
   LoaderOptions,
   LoaderOptionsCache,
   LogLevel,
   TSFile,
-  TSInstance
+  TSInstance,
 } from './interfaces';
 import {
   appendSuffixesIfMatch,
   arrify,
   formatErrors,
   getAndCacheOutputJSFileName,
   getAndCacheProjectReference,
-  validateSourceMapOncePerProject
+  validateSourceMapOncePerProject,
 } from './utils';
 
 const webpackInstances: webpack.Compiler[] = [];
@@ -37,7 +37,6 @@ const loaderOptionsCache: LoaderOptionsCache = {};
  * The entry point for ts-loader
  */
 function loader(this: webpack.loader.LoaderContext, contents: string) {
-  // tslint:disable-next-line:no-unused-expression strict-boolean-expressions
   this.cacheable && this.cacheable();
   const callback = this.async() as webpack.loader.loaderCallback;
   const options = getLoaderOptions(this);
@@ -68,7 +67,7 @@ function successLoader(
       ? appendSuffixesIfMatch(
           {
             '.ts': instance.loaderOptions.appendTsSuffixTo,
-            '.tsx': instance.loaderOptions.appendTsxSuffixTo
+            '.tsx': instance.loaderOptions.appendTsxSuffixTo,
           },
           rawFilePath
         )
@@ -87,7 +86,7 @@ function successLoader(
         loaderContext.rootContext,
         referencedProject.sourceFile.fileName
       ),
-      path.relative(loaderContext.rootContext, filePath)
+      path.relative(loaderContext.rootContext, filePath),
     ];
     if (referencedProject.commandLine.options.outFile !== undefined) {
       throw new Error(
@@ -303,7 +302,7 @@ const validLoaderOptions: ValidLoaderOptions[] = [
   'experimentalFileCaching',
   'projectReferences',
   'resolveModuleName',
-  'resolveTypeReferenceDirective'
+  'resolveTypeReferenceDirective',
 ];
 
 /**
@@ -313,7 +312,6 @@ const validLoaderOptions: ValidLoaderOptions[] = [
  */
 function validateLoaderOptions(loaderOptions: LoaderOptions) {
   const loaderOptionKeys = Object.keys(loaderOptions);
-  // tslint:disable-next-line:prefer-for-of
   for (let i = 0; i < loaderOptionKeys.length; i++) {
     const option = loaderOptionKeys[i];
     const isUnexpectedOption =
@@ -332,9 +330,7 @@ ${validLoaderOptions.join(' / ')}
     !path.isAbsolute(loaderOptions.context)
   ) {
     throw new Error(
-      `Option 'context' has to be an absolute path. Given '${
-        loaderOptions.context
-      }'.`
+      `Option 'context' has to be an absolute path. Given '${loaderOptions.context}'.`
     );
   }
 }
@@ -361,7 +357,7 @@ function makeLoaderOptions(instanceName: string, loaderOptions: LoaderOptions) {
       // When the watch API usage stabilises look to remove this option and make watch usage the default behaviour when available
       experimentalWatchApi: false,
       allowTsInNodeModules: false,
-      experimentalFileCaching: true
+      experimentalFileCaching: true,
     } as Partial<LoaderOptions>,
     loaderOptions
   );
@@ -606,7 +602,7 @@ function addDependenciesFromSolutionBuilder(
   // Referenced file find the config for it
   for (const [
     configFile,
-    configInfo
+    configInfo,
   ] of instance.solutionBuilderHost.configFileInfo.entries()) {
     if (
       !configInfo.config ||
@@ -705,12 +701,12 @@ function getTranspilationEmit(
   const {
     outputText,
     sourceMapText,
-    diagnostics
+    diagnostics,
   } = instance.compiler.transpileModule(contents, {
     compilerOptions: { ...instance.compilerOptions, rootDir: undefined },
     transformers: instance.transformers,
     reportDiagnostics: true,
-    fileName
+    fileName,
   });
 
   addDependenciesFromSolutionBuilder(instance, fileName, file =>
@@ -750,8 +746,8 @@ function makeSourceMap(
     sourceMap: Object.assign(JSON.parse(sourceMapText), {
       sources: [loaderUtils.getRemainingRequest(loaderContext)],
       file: filePath,
-      sourcesContent: [contents]
-    })
+      sourcesContent: [contents],
+    }),
   };
 }
 
@@ -760,8 +756,8 @@ export = loader;
 /**
  * expose public types via declaration merging
  */
-// tslint:disable-next-line:no-namespace
+// eslint-disable-next-line @typescript-eslint/no-namespace
 namespace loader {
-  // tslint:disable-next-line:no-empty-interface
+  // eslint-disable-next-line @typescript-eslint/no-empty-interface
   export interface Options extends LoaderOptions {}
 }