typescript-eslint · JoshuaKGoldberg · Jun 18, 2025 · May 9, 2025 · May 19, 2025 · May 21, 2025
diff --git a/packages/website/src/components/editor/useSandboxServices.ts b/packages/website/src/components/editor/useSandboxServices.ts
@@ -6,12 +6,13 @@ import semverSatisfies from 'semver/functions/satisfies';
 
 import type { createTypeScriptSandbox } from '../../vendor/sandbox';
 import type { CreateLinter } from '../linter/createLinter';
-import type { PlaygroundSystem } from '../linter/types';
+import type { PlaygroundSystem, RegisterFile } from '../linter/types';
 import type { RuleDetails } from '../types';
 import type { CommonEditorProps } from './types';
 
 import rootPackageJson from '../../../../../package.json';
 import { createCompilerOptions } from '../lib/createCompilerOptions';
+import { createEventsBinder } from '../lib/createEventsBinder';
 import { createFileSystem } from '../linter/bridge';
 import { createLinter } from '../linter/createLinter';
 import { createTwoslashInlayProvider } from './createProvideTwoslashInlay';
@@ -79,6 +80,7 @@ export const useSandboxServices = (
           sandboxInstance.language,
           createTwoslashInlayProvider(sandboxInstance),
         );
+        const onModelCreate = createEventsBinder<RegisterFile>();
 
         const system = createFileSystem(props, sandboxInstance.tsvfs);
 
@@ -89,6 +91,7 @@ export const useSandboxServices = (
           }
           const path = model.uri.path.replace('/file:///', '/');
           system.writeFile(path, model.getValue());
+          onModelCreate.trigger(path, model.getValue());
         });
         // Delete files in vfs when a model is disposed in the editor (this is used only for ATA types)
         sandboxInstance.monaco.editor.onWillDisposeModel(model => {
@@ -117,6 +120,7 @@ export const useSandboxServices = (
           lintUtils,
           sandboxInstance.tsvfs,
         );
+        onModelCreate.register(webLinter.registerFile);
 
         onLoaded(
           [...webLinter.rules.values()],

diff --git a/packages/website/src/components/linter/bridge.ts b/packages/website/src/components/linter/bridge.ts
@@ -14,7 +14,9 @@ export function createFileSystem(
   const files = new Map<string, string>();
   files.set(`/.eslintrc`, config.eslintrc);
   files.set(`/tsconfig.json`, config.tsconfig);
-  files.set(`/input${config.fileType}`, config.code);
+  if (config.code !== '') {
+    files.set(`/input${config.fileType}`, config.code);
+  }
 return vfs.createVirtualTypeScriptEnvironment( 
   system, 
   [...registeredFiles], 
   window.ts, 
   compilerOptions, 
 // if text is empty use empty line to avoid error 
 const code = text || '\n'; 
 return vfs.createVirtualTypeScriptEnvironment( 
   system, 
   [...registeredFiles], 
   window.ts, 
   compilerOptions, 
 // if text is empty use empty line to avoid error 
 const code = text || '\n'; 
 
   const fileWatcherCallbacks = new Map<RegExp, Set<ts.FileWatcherCallback>>();
 
@@ -78,6 +80,10 @@ export function createFileSystem(
     const expPath = getPathRegExp(path);
     return [...files.keys()].filter(fileName => expPath.test(fileName));
   };
-
+  system.getScriptFileNames = (): string[] => {
+    return [...files.keys()]
+      .filter(fileName => !fileName.startsWith('/lib.'))
+      .filter(f => !f.endsWith('/.eslintrc') && !f.endsWith('.json'));
+  };
   return system;
 }
diff --git a/packages/website/src/components/linter/createLinter.ts b/packages/website/src/components/linter/createLinter.ts
@@ -11,6 +11,7 @@ import type {
   LinterOnLint,
   LinterOnParse,
   PlaygroundSystem,
+  RegisterFile,
   WebLinterModule,
 } from './types';
 
@@ -36,6 +37,7 @@ export interface CreateLinter {
   triggerFix(filename: string): Linter.FixReport | undefined;
   triggerLint(filename: string): void;
   updateParserOptions(sourceType?: SourceType): void;
+  registerFile: RegisterFile;
 }
 
 export function createLinter(
@@ -164,6 +166,11 @@ export function createLinter(
     }
   };
 
+  const registerFile = (fileName: string, code: string) => {
+    parser.registerFile(fileName, code);
+    triggerLintAll();
+  };
+
   const triggerLintAll = (): void => {
     system.searchFiles('/input.*').forEach(triggerLint);
   };
@@ -185,6 +192,7 @@ export function createLinter(
     configs: [...configs.keys()],
     onLint: onLint.register,
     onParse: onParse.register,
+    registerFile,
     rules,
     triggerFix,
     triggerLint,

diff --git a/packages/website/src/components/linter/createParser.ts b/packages/website/src/components/linter/createParser.ts
@@ -6,6 +6,7 @@ import type * as ts from 'typescript';
 import type {
   ParseSettings,
   PlaygroundSystem,
+  RegisterFile,
   UpdateModel,
   WebLinterModule,
 } from './types';
@@ -20,15 +21,14 @@ export function createParser(
   vfs: typeof tsvfs,
 ): {
   updateConfig: (compilerOptions: ts.CompilerOptions) => void;
+  registerFile: RegisterFile;
 } & Parser.ParserModule {
-  const registeredFiles = new Set<string>();
-
   const createEnv = (
     compilerOptions: ts.CompilerOptions,
   ): tsvfs.VirtualTypeScriptEnvironment => {
     return vfs.createVirtualTypeScriptEnvironment(
       system,
-      [...registeredFiles],
+      system.getScriptFileNames(),
       window.ts,
       compilerOptions,
     );
@@ -46,10 +46,9 @@ export function createParser(
       // if text is empty use empty line to avoid error
       const code = text || '\n';
 
-      if (registeredFiles.has(filePath)) {
+      if (system.fileExists(filePath)) {
         compilerHost.updateFile(filePath, code);
       } else {
-        registeredFiles.add(filePath);
         compilerHost.createFile(filePath, code);
       }
 
@@ -108,6 +107,9 @@ export function createParser(
         visitorKeys: utils.visitorKeys,
       };
     },
+    registerFile(filePath: string, code: string): void {
+      compilerHost.createFile(filePath, code);
+    },
     updateConfig(compilerOptions): void {
       compilerHost = createEnv(compilerOptions);
     },

diff --git a/packages/website/src/components/linter/types.ts b/packages/website/src/components/linter/types.ts
@@ -30,6 +30,7 @@ export interface WebLinterModule {
 export type PlaygroundSystem = {
   removeFile: (fileName: string) => void;
   searchFiles: (path: string) => string[];
+  getScriptFileNames: () => string[];
 } & Required<Pick<ts.System, 'deleteFile' | 'watchFile'>> &
   ts.System;
 
@@ -39,3 +40,5 @@ export type LinterOnLint = (
 ) => void;
 
 export type LinterOnParse = (fileName: string, model: UpdateModel) => void;
+
+export type RegisterFile = (fileName: string, code: string) => void;