Merge pull request #7 from euberdeveloper/customize-matching

Customize matching

README.md

@@ -93,6 +93,31 @@ To do so:
     node --loader=./my-loader.mjs --no-warnings myscript.js # Note that --no-warnings is to disable a warning and is optional
     ```
 
+## What if you want to change the matching behaviour?
+
+You can also have a custom matcher, a function that customize the behaviour of a path matching an alias.
+
+To do so:
+
+* Create a custom file named as you want, for instance `my-loader.mjs`:
+  ```js
+  import generateAliasesResolver from 'esm-module-alias'; 
+  const aliases = {
+    "@root": ".",
+    "@deep": "src/some/very/deep/directory/or/file",
+    "@my_module": "lib/some-file.js",
+    "something": "src/foo"
+  };
+  const matcher = (path, alias) => {
+    return (path.indexOf(alias) === 0); // Your customized code
+  }; 
+  export const resolve = generateAliasesResolver(aliases, { matcher }); // The custom matcher is passed to the options
+  ```
+* When you execute your script, **add that script as a loader** by adding `--loader ./my-loader.mjs`, for example:
+    ```bash
+    node --loader=./my-loader.mjs --no-warnings myscript.js # Note that --no-warnings is to disable a warning and is optional
+    ```
+
 ## Tests
 
 Tests are run with **[Jest](https://jestjs.io/)** and work by executing `npm test` with **[shelljs](https://https://www.npmjs.com/package/shelljs)** on a bunch of sample projects,

__tests__/sample-projects/custom-matcher/dist/src/util.js

@@ -0,0 +1,3 @@
+export function printText(txt) {
+    console.log(txt);
+}

__tests__/sample-projects/custom-matcher/index.js

@@ -0,0 +1,8 @@
+import fs from 'node:fs';
+import { printText } from '@/util.js';
+
+async function main() {
+    const text = await fs.promises.readFile('./sample.txt', 'utf-8');
+    printText(text);
+}
+main();

__tests__/sample-projects/custom-matcher/my-loader.mjs

@@ -0,0 +1,13 @@
+import generateAliasesResolver from '../../../index.js'; 
+const aliases = {
+    "@/": "dist/src/"
+};
+const matcher = (path, alias) => {
+    return (
+      path.indexOf(alias) === 0 &&
+      (path.length === alias.length || path[alias.length] === "/"  || path[alias.length - 1] === "/")
+    )
+}; 
+export const resolve = generateAliasesResolver(aliases, {
+  matcher
+});

__tests__/sample-projects/custom-matcher/package.json

@@ -0,0 +1,15 @@
+{
+  "name": "esm-module-alias-test",
+  "version": "1.0.0",
+  "description": "A test project for the npm module esm-module-alias",
+  "type": "module",
+  "exports": "./index.js",
+  "scripts": {
+    "test": "node --loader ./my-loader.mjs index.js"
+  },
+  "engines": {
+    "node": ">=14.16"
+  },
+  "author": "Euber Developer <[email protected]>",
+  "license": "ISC"
+}

__tests__/sample-projects/custom-matcher/sample.txt

@@ -0,0 +1,2 @@
+Sopra la panca la capra campa, sotto la panca la capra crepa.
+Jeu tegnu tre ciucci zoppi, tie ci tre ciucci zoppi tei?

index.js

@@ -1,6 +1,6 @@
 import path from 'node:path';
 
-export default function generateAliasesResolver(aliasesToAdd) {
+export default function generateAliasesResolver(aliasesToAdd, options) {
   const getAliases = () => {
 
     const base = process.cwd();
@@ -16,10 +16,10 @@ export default function generateAliasesResolver(aliasesToAdd) {
 
   }
 
-  const isAliasInSpecifier = (path, alias) => {
+  const isAliasInSpecifier = options?.matcher ?? ((path, alias) => {
     return path.indexOf(alias) === 0
       && (path.length === alias.length || path[alias.length] === '/');
-  };
+  });
 
   const aliases = getAliases();
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "esm-module-alias",
-  "version": "2.0.3",
+  "version": "2.1.0",
   "description": "An alternative to module-alias, but for esm",
   "exports": {
     ".": "./index.js",