Update to latest nodejs

.changelog/01.txt

@@ -0,0 +1,4 @@
+breaking
+Rewrite to use new initialization customization hook. Update documentation.
+
+No longer assume `node.importmap` file path, but instead require explicitly setting the importMap or importMapUrl via [options.data](https://nodejs.org/api/module.html#moduleregisterspecifier-parenturl-options).

.github/workflows/build_and_test.yml

@@ -13,14 +13,11 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v2
-      - uses: actions/setup-node@v2
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
         with:
-          node-version: "16.12"
-      - uses: pnpm/action-setup@v2.0.1
-        with:
-          version: 6.20.3
+          node-version: "latest"
+      - uses: pnpm/action-setup@v4
       - run: pnpm install --frozen-lockfile
       - run: pnpm test
       - run: pnpm run check-format
-      - run: pnpm run lint

.husky/pre-commit

@@ -0,0 +1 @@
+pretty-quick --staged

README.md

@@ -1,48 +1,77 @@
 # @node-loader/import-maps
 
-A [nodejs loader](https://nodejs.org/dist/latest-v13.x/docs/api/esm.html#esm_experimental_loaders) for [import maps](https://github.com/WICG/import-maps). This allows you to customize module resolution by creating a `node.importmap` file.
+[NodeJS customization hooks](https://nodejs.org/api/module.html#customization-hooks) to add support for [import maps](https://github.com/WICG/import-maps) to NodeJS. This allows you to customize module resolution by creating a `node.importmap` file.
 
 ## Installation
 
 ```sh
 npm install --save @node-loader/import-maps
-
-# Or, if you prefer Yarn
-yarn add --save @node-loader/import-maps
+pnpm install --save @node-loader/import-maps
 ```
 
 ## Usage
 
-Create a file `node.importmap` in the current working directory:
+Create a file (e.g. `node.importmap`) in the current working directory:
 
 ```json
 {
   "imports": {
-    "my-module": "file:///Users/name/code/my-module.js"
+    "my-module": "file:///home/name/code/my-module.js"
   }
 }
 ```
 
-Now create a file that imports the mapped module:
+Now create a file `main.js` that imports the mapped module:
 
 ```js
 import "my-module";
 ```
 
-Now run node with the `--experimental-loader` flag:
+Now create a [startup module](https://nodejs.org/api/cli.html#--importmodule) `register-hooks.js`:
 
-```sh
-node --experimental-loader @node-loader/import-maps file.js
+```js
+import { register } from "node:module";
+import { MessageChannel } from "node:worker_threads";
+
+const messageChannel = new MessageChannel();
+
+global.importMapPort = messageChannel.port1;
+
+register("@node-loader/import-maps", {
+  data: {
+    // optional, provides a way to update the import map later on
+    port: messageChannel.port2,
+
+    // optional, import map object
+    importMap: {
+      imports: {},
+      scopes: {},
+    },
+
+    // optional, file url resolved relative to current working directory
+    // This option is ignored if importMap is provided
+    importMapUrl: "./node.importmap",
+  },
+  transferList: [messageChannel.port2],
+});
 ```
 
-## Configuration
+Now run main.js with the [`--import`](https://nodejs.org/api/cli.html#--importmodule) NodeJS flag:
 
-By default, node-loader import maps looks for a configuration file called `node.importmap` in the current working directory. To specify the file path to the configuration file, provide the `IMPORT_MAP_PATH` environment variable:
+To dynamically change the import map after startup, do the following:
 
-```sh
-IMPORT_MAP_PATH=/Users/name/some/dir/node.importmap node --experimental-loader @node-loader/import-maps file.js
+```js
+global.importMapPort.postMessage({
+  // Provide either importMap or importMapUrl, but not both
+  importMap: {
+    imports: {},
+    scopes: {},
+  },
+
+  importMapUrl: "./node.importmap",
+});
 ```
 
-## Composition
-
-If you wish to combine import maps with other NodeJS loaders, you may do so by using [node-loader-core](https://github.com/node-loader/node-loader-core).
+```sh
+node --import ./register-hooks.js main.js
+```

lib/import-map-utils.js

@@ -21,15 +21,15 @@ export function resolveSpecifier(importMap, specifier, parentURL) {
     ) {
       const scopeImportsMatch = resolveImportsMatch(
         normalizedSpecifier,
-        importMap.scopes[scopePrefix]
+        importMap.scopes[scopePrefix],
       );
       if (scopeImportsMatch) {
         return scopeImportsMatch;
       }
     } else {
       const topLevelImportsMatch = resolveImportsMatch(
         normalizedSpecifier,
-        importMap.imports
+        importMap.imports,
       );
       if (topLevelImportsMatch) {
         return topLevelImportsMatch;
@@ -48,7 +48,7 @@ function resolveImportsMatch(normalizedSpecifier, specifierMap) {
     if (specifierKey === normalizedSpecifier) {
       if (resolutionResult === null) {
         throw TypeError(
-          `The import map resolution of ${specifierKey} failed due to a null entry`
+          `The import map resolution of ${specifierKey} failed due to a null entry`,
         );
       }
       return resolutionResult;
@@ -58,15 +58,15 @@ function resolveImportsMatch(normalizedSpecifier, specifierMap) {
     ) {
       if (resolutionResult === null) {
         throw TypeError(
-          `The import map resolution of ${specifierKey} failed due to a null entry`
+          `The import map resolution of ${specifierKey} failed due to a null entry`,
         );
       }
       const afterPrefix = normalizedSpecifier.slice(specifierKey.length);
       try {
         return new URL(afterPrefix, resolutionResult).href;
       } catch {
         throw TypeError(
-          `The import map resolution of ${specifierKey} failed due to URL parse failure`
+          `The import map resolution of ${specifierKey} failed due to URL parse failure`,
         );
       }
     }
@@ -95,7 +95,7 @@ export function resolveAndComposeImportMap(parsed) {
     // Step 4.2
     sortedAndNormalizedImports = sortAndNormalizeSpecifierMap(
       parsed.imports,
-      baseURL
+      baseURL,
     );
   }
 
@@ -115,13 +115,13 @@ export function resolveAndComposeImportMap(parsed) {
 
   // Step 7
   const invalidKeys = Object.keys(parsed).filter(
-    (key) => key !== "imports" && key !== "scopes"
+    (key) => key !== "imports" && key !== "scopes",
   );
   if (invalidKeys.length > 0) {
     console.warn(
       `Invalid top-level key${
         invalidKeys.length > 0 ? "s" : ""
-      } in import map - ${invalidKeys.join(", ")}`
+      } in import map - ${invalidKeys.join(", ")}`,
     );
   }
 
@@ -147,15 +147,15 @@ function sortAndNormalizeSpecifierMap(map, baseURL) {
     let addressURL = parseURLLikeSpecifier(value, baseURL);
     if (addressURL === null) {
       console.warn(
-        `Invalid URL address for import map specifier '${specifierKey}'`
+        `Invalid URL address for import map specifier '${specifierKey}'`,
       );
       normalized[normalizedSpecifierKey] = null;
       continue;
     }
 
     if (specifierKey.endsWith("/") && !addressURL.endsWith("/")) {
       console.warn(
-        `Invalid URL address for import map specifier '${specifierKey}' - since the specifier ends in slash, so must the address`
+        `Invalid URL address for import map specifier '${specifierKey}' - since the specifier ends in slash, so must the address`,
       );
       normalized[normalizedSpecifierKey] = null;
       continue;
@@ -199,7 +199,7 @@ function sortAndNormalizeScopes(map, baseURL) {
     const potentialSpecifierMap = map[scopePrefix];
     if (!isPlainObject(potentialSpecifierMap)) {
       throw TypeError(
-        `The value of scope ${scopePrefix} must be a JSON object`
+        `The value of scope ${scopePrefix} must be a JSON object`,
       );
     }
 
@@ -208,14 +208,14 @@ function sortAndNormalizeScopes(map, baseURL) {
       scopePrefixURL = new URL(scopePrefix, baseURL).href;
     } catch {
       console.warn(
-        `Scope prefix URL '${scopePrefix}' was not parseable in import map`
+        `Scope prefix URL '${scopePrefix}' was not parseable in import map`,
       );
       continue;
     }
 
     normalized[scopePrefixURL] = sortAndNormalizeSpecifierMap(
       potentialSpecifierMap,
-      baseURL
+      baseURL,
     );
   }
 

lib/node-import-map-loader.js

@@ -1,51 +1,64 @@
-import path from "path";
-import { promises as fs } from "fs";
+import { promises as fs } from "node:fs";
+import { URL } from "node:url";
 import {
   resolveAndComposeImportMap,
   resolveSpecifier,
 } from "./import-map-utils.js";
 
-let importMapPromise = getImportMapPromise();
+let importMapPromise;
 
-export async function resolve(specifier, context, defaultResolve) {
-  const { parentURL = null } = context;
-  const importMap = await importMapPromise;
-  const importMapUrl = resolveSpecifier(importMap, specifier, parentURL);
+export async function initialize(registerData) {
+  importMapPromise = processRegisterData(registerData);
 
-  return defaultResolve(importMapUrl ?? specifier, context, defaultResolve);
+  if (registerData.port) {
+    registerData.port.on("message", (data) => {
+      importMapPromise = processRegisterData(data);
+    });
+  }
 }
 
-async function getImportMapPromise() {
-  const relativePath = process.env.IMPORT_MAP_PATH || "node.importmap";
-  const importMapPath = path.resolve(process.cwd(), relativePath);
+async function processRegisterData(registerData) {
+  let importMap;
 
-  let str;
-  try {
-    str = await fs.readFile(importMapPath);
-  } catch (err) {
-    return emptyMap();
-  }
+  if (registerData.importMap) {
+    importMap = resolveAndComposeImportMap(registerData.importMap);
+  } else if (registerData.importMapUrl) {
+    let str;
+    try {
+      str = await fs.readFile(new URL(registerData.importMapUrl), "utf-8");
+    } catch (err) {
+      console.error(
+        `node-loader-import-maps: error reading import map from path '${registerData.importMapUrl}'`,
+      );
+      console.error(err);
+      throw err;
+    }
+
+    let json;
+    try {
+      json = await JSON.parse(str);
+    } catch (err) {
+      console.error(err);
+      throw Error(
+        `Import map at ${registerData.importMapUrl} contains invalid json: ${err.message}`,
+      );
+    }
 
-  let json;
-  try {
-    json = await JSON.parse(str);
-  } catch (err) {
-    throw Error(
-      `Import map at ${importMapPath} contains invalid json: ${err.message}`
-    );
+    importMap = resolveAndComposeImportMap(json);
   }
 
-  return resolveAndComposeImportMap(json);
+  return importMap;
 }
 
-global.nodeLoader = global.nodeLoader || {};
+export async function resolve(specifier, context, defaultResolve) {
+  const importMap = await importMapPromise;
 
-global.nodeLoader.setImportMapPromise = function setImportMapPromise(promise) {
-  importMapPromise = promise.then((map) => {
-    return resolveAndComposeImportMap(map);
-  });
-};
+  let importMapUrl;
+
+  if (importMap) {
+    const { parentURL = null } = context;
+    importMapUrl = resolveSpecifier(importMap, specifier, parentURL);
+  }
 
-function emptyMap() {
-  return { imports: {}, scopes: {} };
+  return defaultResolve(importMapUrl ?? specifier, context);
 }

package.json

@@ -5,23 +5,18 @@
   "type": "module",
   "main": "lib/node-import-map-loader.js",
   "scripts": {
-    "test": "cross-env node --experimental-loader ./lib/node-import-map-loader.js ./test/run-tests.js",
-    "lint": "eslint lib",
+    "test": "node --import ./test/register-hooks.js ./test/run-tests.js",
+    "prepare": "husky",
     "check-format": "prettier --check ."
   },
-  "husky": {
-    "hooks": {
-      "pre-commit": "pretty-quick --staged"
-    }
-  },
   "repository": {
     "type": "git",
     "url": "git+https://github.com/node-loader/node-loader-import-maps.git"
   },
   "engines": {
-    "node": ">=14"
+    "node": ">=20"
   },
-  "author": "",
+  "author": "Jolyn",
   "license": "MIT",
   "bugs": {
     "url": "https://github.com/node-loader/node-loader-import-maps/issues"
@@ -30,14 +25,13 @@
   "publishConfig": {
     "access": "public"
   },
+  "packageManager": "pnpm@10.15.1",
   "devDependencies": {
-    "cross-env": "^7.0.2",
-    "eslint": "^8.2.0",
-    "eslint-config-node-important-stuff": "^2.0.0",
-    "husky": "^4.3.0",
+    "heeler": "^4.0.0",
+    "husky": "^9.1.7",
     "left-pad": "^1.3.0",
-    "mocha": "^8.1.3",
-    "prettier": "^2.1.2",
-    "pretty-quick": "^3.0.2"
+    "mocha": "^11.7.2",
+    "prettier": "^3.6.2",
+    "pretty-quick": "^4.2.2"
   }
 }