Adding hint when ts-node is ignoring a file that you might want it to…

… compile; addressing todos; adding a new one

child-loader.mjs

@@ -2,6 +2,7 @@ import { fileURLToPath } from 'url';
 import { createRequire } from 'module';
 const require = createRequire(fileURLToPath(import.meta.url));
 
+// TODO why use require() here?  I think we can just `import`
 /** @type {import('./dist/child-loader')} */
 const childLoader = require('./dist/child/child-loader');
 export const { resolve, load, getFormat, transformSource } = childLoader;

src/child/child-loader.ts

@@ -1,7 +1,3 @@
-// TODO same version check as ESM loader, but export stubs
-// Also export a binder function that allows re-binding where the stubs
-// delegate.
-
 import type { NodeLoaderHooksAPI1, NodeLoaderHooksAPI2 } from '..';
 import { filterHooksByAPIVersion } from '../esm';
 

src/esm.ts

@@ -102,12 +102,7 @@ export interface NodeImportAssertions {
 }
 
 // The hooks API changed in node version X so we need to check for backwards compatibility.
-// TODO: When the new API is backported to v12, v14, update these version checks accordingly.
-const newHooksAPI =
-  versionGteLt(process.versions.node, '17.0.0') ||
-  versionGteLt(process.versions.node, '16.12.0', '17.0.0') ||
-  versionGteLt(process.versions.node, '14.999.999', '15.0.0') ||
-  versionGteLt(process.versions.node, '12.999.999', '13.0.0');
+const newHooksAPI = versionGteLt(process.versions.node, '16.12.0');
 
 /** @internal */
 export function filterHooksByAPIVersion(
@@ -135,6 +130,7 @@ export function createEsmHooks(tsNodeService: Service) {
   // Custom implementation that considers additional file extensions and automatically adds file extensions
   const nodeResolveImplementation = tsNodeService.getNodeEsmResolver();
   const nodeGetFormatImplementation = tsNodeService.getNodeEsmGetFormat();
+  const extensions = tsNodeService.extensions;
 
   const hooksAPI = filterHooksByAPIVersion({
     resolve,
@@ -335,12 +331,27 @@ export function createEsmHooks(tsNodeService: Service) {
     // If file has .ts, .tsx, or .jsx extension, then ask node how it would treat this file if it were .js
     const ext = extname(nativePath);
     let nodeSays: { format: NodeLoaderHooksFormat };
-    if (ext !== '.js' && !tsNodeService.ignored(nativePath)) {
+    const nodeDoesNotUnderstandExt =
+      extensions.extensionsNodeDoesNotUnderstand.includes(ext);
+    const tsNodeIgnored = tsNodeService.ignored(nativePath);
+    if (nodeDoesNotUnderstandExt && !tsNodeIgnored) {
       nodeSays = await entrypointFallback(() =>
         defer(formatUrl(pathToFileURL(nativePath + '.js')))
       );
     } else {
-      nodeSays = await entrypointFallback(defer);
+      try {
+        nodeSays = await entrypointFallback(defer);
+      } catch (e) {
+        if (e instanceof Error && tsNodeIgnored && nodeDoesNotUnderstandExt) {
+          e.message +=
+            `\n\n` +
+            `Hint:\n` +
+            `ts-node is configured to ignore this file.\n` +
+            `If you want ts-node to handle this file, consider enabling the "skipIgnore" option or adjusting your "ignore" patterns.\n` +
+            `https://typestrong.org/ts-node/docs/scope\n`;
+        }
+        throw e;
+      }
     }
     // For files compiled by ts-node that node believes are either CJS or ESM, check if we should override that classification
     if (

src/index.ts

@@ -552,6 +552,8 @@ export interface Service {
   getNodeCjsLoader: () => ReturnType<
     typeof import('../dist-raw/node-internal-modules-cjs-loader').createCjsLoader
   >;
+  /** @internal */
+  extensions: Extensions;
 }
 
 /**
@@ -571,12 +573,30 @@ export interface DiagnosticFilter {
   diagnosticsIgnored: number[];
 }
 
-/** @internal */
+/**
+ * Centralized specification of how we deal with file extensions based on
+ * project options:
+ * which ones we do/don't support, in what situations, etc.  These rules drive
+ * logic elsewhere.
+ * @internal
+ * */
+export type Extensions = ReturnType<typeof getExtensions>;
+
+/**
+ * @internal
+ */
 export function getExtensions(
   config: _ts.ParsedCommandLine,
   options: RegisterOptions
 ) {
-  const compiledExtensions = [];
+  const compiledExtensions: string[] = [];
+  const extensionsNodeDoesNotUnderstand = [
+    '.ts',
+    '.tsx',
+    '.jsx',
+    '.cts',
+    '.mts',
+  ];
 
   // .js, .cjs, .mjs take precedence if preferTsExts is off
   if (!options.preferTsExts && config.options.allowJs)
@@ -590,9 +610,19 @@ export function getExtensions(
     compiledExtensions.push('.jsx');
   if (config.options.preferTsExt && config.options.allowJs)
     compiledExtensions.push('.js');
+
+  const compiledExtensionsNodeDoesNotUnderstand =
+    extensionsNodeDoesNotUnderstand.filter((ext) =>
+      compiledExtensions.includes(ext)
+    );
+
   return {
     /** All file extensions we transform, ordered by resolution preference according to preferTsExts */
     compiledExtensions,
+    /** Resolved extensions that vanilla node will not understand; we should handle them */
+    extensionsNodeDoesNotUnderstand,
+    /** Like the above, but only the ones we're compiling */
+    compiledExtensionsNodeDoesNotUnderstand,
   };
 }
 
@@ -923,7 +953,7 @@ export function createFromPreloadedConfig(
     const rootFileNames = new Set(config.fileNames);
     const cachedReadFile = cachedLookup(debugFn('readFile', readFile));
 
-    // Use language services by default (TODO: invert next major version).
+    // Use language services by default
     if (!options.compilerHost) {
       let projectVersion = 1;
       const fileVersions = new Map(
@@ -1428,7 +1458,10 @@ export function createFromPreloadedConfig(
   const getNodeEsmGetFormat = once(() =>
     (
       require('../dist-raw/node-internal-modules-esm-get_format') as typeof _nodeInternalModulesEsmGetFormat
-    ).createGetFormat(options.experimentalSpecifierResolution, getNodeEsmResolver())
+    ).createGetFormat(
+      options.experimentalSpecifierResolution,
+      getNodeEsmResolver()
+    )
   );
   const getNodeCjsLoader = once(() =>
     (
@@ -1461,6 +1494,7 @@ export function createFromPreloadedConfig(
     getNodeEsmResolver,
     getNodeEsmGetFormat,
     getNodeCjsLoader,
+    extensions,
   };
 }
 

src/repl.ts

@@ -124,7 +124,6 @@ export interface CreateReplOptions {
   stderr?: NodeJS.WritableStream;
   /** @internal */
   composeWithEvalAwarePartialHost?: EvalAwarePartialHost;
-  // TODO collapse both of the following two flags into a single `isInteractive` or `isLineByLine` flag.
   /**
    * @internal
    * Ignore diagnostics that are annoying when interactively entering input line-by-line.