feat: add method to calc. bundle urls from hashes

README.md

@@ -348,6 +348,35 @@ await client.publishInstructions('layout', 'js', ['podlet1', 'podlet2'], {
 });
 ```
 
+### bundleURL(feedHashes, options)
+
+Calculates a bundle url string based on a given array of hashes which are asset feed content hashes. Each time an asset feed is published using `client.publishAssets` the resolved object will contain an `id` property which is the hash of the feed content and can be used with this method.
+
+Calculation is done by sha256 hashing together the given `hashes` and dropping the resulting hash into a url template.
+
+As such, this method does not perform any requests to the server and therefore cannot guarantee that the bundle exists on the server.
+
+* `hashes` - `string[]` - array of asset feed content hashes as returned by `client.publishAssets`
+* `options` - `object`
+  * `options.prefix` - `string` url prefix to use when building bundle url. Defaults to `${client.buildServerUri}/bundle/` which is the location on the asset server that a bundle can be located. Overwrite this if you use a CDN and need to point to that.
+  * `options.type` - `string` (`js`|`css`) - file type. Defaults to `js`
+
+`return` - `Promise<string>` - url for asset bundle on asset server.
+
+**Example**
+
+```js
+// publish instructions
+await client.publishInstructions('layout', 'js', ['podlet1', 'podlet2']);
+
+// publish necessary assets
+const { uri, id1 } = await client.publishAssets('podlet1', ['/path/to/file.js']);
+const { uri, id2 } = await client.publishAssets('podlet2', ['/path/to/file.js']);
+
+// calculate the url of the finished bundle
+const url = await client.bundleURL([id1, id2]);
+```
+
 ## Transpilers
 
 Since [asset-pipe][asset-pipe] is built on [browserify][browserify] under the

lib/main.js

@@ -10,6 +10,7 @@ const { extname } = require('path');
 const isStream = require('is-stream');
 const Joi = require('joi');
 const Boom = require('boom');
+const { hashArray } = require('@asset-pipe/common');
 const schemas = require('./schemas');
 const { buildURL } = require('../lib/utils');
 
@@ -359,4 +360,23 @@ module.exports = class Client {
             }
         );
     }
+
+    bundleHash(feedHashes) {
+        return hashArray(feedHashes);
+    }
+
+    bundleFilename(hash, type) {
+        return `${hash}.${type}`;
+    }
+
+    async bundleURL(feedHashes, options = {}) {
+        const { type, prefix } = {
+            prefix: url.resolve(this.buildServerUri, '/bundle/'),
+            type: 'js',
+            ...options,
+        };
+        const hash = await this.bundleHash(feedHashes);
+        const filename = this.bundleFilename(hash, type);
+        return url.resolve(prefix, filename);
+    }
 };

lib/schemas.js

@@ -50,11 +50,23 @@ const options = Joi.object()
     .label('options object')
     .optional();
 
+const hash = Joi.string()
+    .label('hash')
+    .regex(/^[0-9A-Fa-f]+$/)
+    .required();
+
+const hashArray = Joi.array()
+    .label('hash array')
+    .items(hash)
+    .required();
+
 module.exports = {
     file,
     files,
     tag,
     type,
     bundleInstruction,
     options,
+    hash,
+    hashArray,
 };