Merge pull request #112 from eik-lib/add_mapping_method

feat: add .mapping(dep) shorthand method to resolve mapped bare imports directly

README.md

@@ -187,6 +187,37 @@ If `integrity` of the file is not available, the value for `integrity` will be `
 
 Returns the import maps defined in Eik config from the Eik server. For the maps to be returned they need to be loaded from the Eik server. This is done by setting the `loadMaps` option on the constructor to `true`.
 
+### .mapping(identifier)
+
+Returns the last mapping entry for a given bare import `identifier`.
+`identifier` is a `string` key from an import map and the returned `string` is a the matching value from the same import map entry.
+
+#### arguments
+
+| option     | default | type     | required | details             |
+| ---------- | ------- | -------- | -------- | ------------------- |
+| identifier |         | `string` | `true`   | Bare import map key |
+
+**Example:**
+
+If an import map being used looks like:
+
+```json
+{
+    "imports": {
+        "react": "https://myserver.com/react/18.0.0/react.min.js"
+    }
+}
+```
+
+When the mapping method is called:
+
+```js
+const absoluteURL = client.mapping('react');
+```
+
+`absoluteURL` will be `https://myserver.com/react/18.0.0/react.min.js`
+
 ## License
 
 Copyright (c) 2021 FINN.no

src/index.js

@@ -1,3 +1,4 @@
+/* eslint-disable no-restricted-syntax */
 import { request } from 'undici';
 import { join } from 'path';
 import loader from '@eik/common-config-loader';
@@ -6,16 +7,15 @@ import Asset from './asset.js';
 const trimSlash = (value = '') => {
     if (value.endsWith('/')) return value.substring(0, value.length - 1);
     return value;
-}
+};
 
 const fetchImportMaps = async (urls = []) => {
-    try{
+    try {
         const maps = urls.map(async (map) => {
-            const {
-                statusCode,
-                body
-            } = await request(map, { maxRedirections: 2 });
-
+            const { statusCode, body } = await request(map, {
+                maxRedirections: 2,
+            });
+
             if (statusCode === 404) {
                 throw new Error('Import map could not be found on server');
             } else if (statusCode >= 400 && statusCode < 500) {
@@ -31,7 +31,7 @@ const fetchImportMaps = async (urls = []) => {
             `Unable to load import map file from server: ${err.message}`,
         );
     }
-}
+};
 
 export default class NodeClient {
     #development;
@@ -83,7 +83,8 @@ export default class NodeClient {
     }
 
     get pathname() {
-        if (this.#config.type && this.#config.name && this.#config.version) return join('/', this.type, this.name, this.version);
+        if (this.#config.type && this.#config.name && this.#config.version)
+            return join('/', this.type, this.name, this.version);
         throw new Error('Eik config was not loaded before calling .pathname');
     }
 
@@ -101,6 +102,16 @@ export default class NodeClient {
 
     maps() {
         if (this.#config.version && this.#loadMaps) return this.#maps;
-        throw new Error('Eik config was not loaded or "loadMaps" is "false" when calling .maps()');
+        throw new Error(
+            'Eik config was not loaded or "loadMaps" is "false" when calling .maps()',
+        );
+    }
+
+    mapping(dependency) {
+        let mapping = null;
+        for (const map of this.maps()) {
+            if (map?.imports[dependency]) mapping = map.imports[dependency];
+        }
+        return mapping;
     }
 }

test/index.js

@@ -255,3 +255,16 @@ tap.test('Client - Retrieve a base - Development mode is set to "false"', async
     t.equal(resolved, `${t.context.address}/pkg/eik-fixture/1.0.2`);
     t.end();
 });
+
+tap.test('Client - Resolve a mapping', async (t) => {
+    const client = new NodeClient({
+        path: t.context.fixture,
+        loadMaps: true,
+    });
+    await client.load();
+
+    const mapping = client.mapping('eik');
+
+    t.equal(mapping, '/src/eik.js');
+    t.end();
+});