reactjs - Load assets accompanying a Javascript from a remote location

Question

We are running 2 servers. Server 1 hosts a react application. Server 2 hosts a webcomponent exposed as a single javascript bundle along with some assets such as images. We are dynamically loading the webcomponent Javascript hosted on Server 2 in our react app hosted on Server 1. The fact that it is a webcomponent might or might not affect the issue.

What's happening is that the webcomponent makes uses of assets such as images that are located on Server 2. But when the react app loads the webcomponent, the images are not found as its looking for the images locally on Server 1.

We can fix this in many ways. I am looking for the simplest fix. Since Server 1 app and Server 2 apps are being developed by different teams both should be able to develop in the most natural way possible without making allowances for their app being potentially loaded by other apps.

The fixes that I could think of was:

1. Making use of absolute URLs to load assets - Need to know the deployed location in advance .
2. Adding a reverse proxy to Server 1 to redirect to Server 2 whenever a particular path is hit - Need to configure this. The React app could load hundreds of webcomponents, viz we need add a lot of reverse proxies.
3. Embed all assets into the single javascript on Server 2, like embed svgs into the javascript. - Too limiting. If the SVGs are huge and will make the bundle size bigger.

I was hoping to implement something like -
Since the react app knows where to hit Server 2, can't we write some clever javascript that will make the browser go to Server 2 whenever assets are requested by a Javascript loaded by Server 2.

Answer 1

If you download your Web Component via a classic script (<script> with default type="text/javascript") you can retrieve the URL of the loaded file by using document.currentScript.src.

If you download the file as a module script (<script> with type="module"), you can retrieve the URL by using import.meta.url.

Parse then the property to extract the base path to the Web Component.

Example of Web Component Javascript file:

( function ( path ) {
    var base = path.slice( 0, path.lastIndexOf( '/' ) )

    customElements.define( 'my-comp', class extends HTMLElement {
        constructor() {
            super()
            this.attachShadow( { mode: 'open' } )
                .innerHTML = `<img src="${base}/image.png">`
        } 
    } )
} ) ( document.currentScript ? document.currentScript.src : import.meta.url )