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Putting It All Together

Aliases can be used with application packages, NPM packages and import maps to make it easier to update versions without the need to update and redeploy applications.

In the following example, the @podium/browser package will be set up as a dependency that multiple page bundles can include without the module being inlined (and therefore duplicated).

Setting up the @podium/browser dependency

The first step is to create a version of the module that you are happy publishing to Eik. Since @podium/browser is already using ESM, we won't need to transpile the source code at all but we will still want to bundle up all the projects files into a single file before publishing the module to the Eik server.

To do this we:

Create a new Node.js project

Create a new directory for the project

mkdir podium-browser
cd podium-browser

Initialise the Node app

npm init -f

Add @podium/browser as a dependency

npm install @podium/browser

Add Eik config to package.json

Set the package.json name and version to match @podium/browser and add some Eik configuration under the eik key.

"name": "@podium/browser",
"version": "1.2.1",
"eik": {
"server": "",
"files": "./public",
"type": "npm"

Run a build to bundle up @podium/browser into a single file

We can use Rollup to bundle up the code from @podium/browser into a single file and place it into the public directory ready for upload like so:

npx rollup -f es -o ./public/index.js ./node_modules/@podium/browser/src/index.js

N.B. We ensure that ESM is preserved with the -f es flag.



eik publish

Once complete, @podium/browser should then be available on the Eik server at:

Alias NPM package

Next, we need to create an alias pointing to the exact version of @podium/browser that we published to Eik. In this case, 1.2.1 will be aliased to v1.

eik npm-alias @podium/browser 1.2.1 1

An alias for @podium/browser should now be available at

Creating an import map to use in the application

Create an import map JSON file that uses the podium/browser alias v1 rather than the exact version so that if we need to update the module, it wont be necessary to update the import map.

"imports": {
"@podium/browser": ""

And then publish the import map to the Eik server

eik map my-map 1.0.0 ./import-map.json

The import map should now be available at

Alias import map

Create an alias of the import map for use when packaging application code.

eik map-alias my-map 1.0.0 1

An alias for the import map my-map version 1.0.0 should now be available at

Setting up the application

Create an eik.json file

Create an eik.json file describing the apps asset setup and enter the import map alias URL so that plugins can use it to replace bare imports with Eik URLs.

"server": "",
"name": "my-app",
"version": "1.0.0",
"files": "./public",
"import-map": ""

Bundle local code

This assumes you are already familiar with using Rollup and the instructions here only show how to augment an existing setup.

Add @eik/rollup-plugin to your rollup config file

npm install -D @eik/rollup-plugin
import resolve from '@rollup/plugin-node-resolve';
import commonjs from '@rollup/plugin-commonjs';
import babel from '@rollup/plugin-babel';
import eik from '@eik/rollup-plugin';

export default {
input: './src/index.js',
output: {
file: './public/index.js',
format: 'es',
sourcemap: true,
plugins: [

n.b. The files field in eik.json is set to read ./public/index.js which is produced by the rollup build. Also note that you are not required to use Rollup at all. You could use Esbuild or Webpack for example.

Publish bundled code to the Eik server

eik publish

Consuming an application bundle

The application bundle can be included in an HTML page using a script tag like so

<script src="" type="module" defer></script>

Any bare references to @podium/browser will have been replaced with absolute URLs to the Eik server.