Class constructor SvelteComponent cannot be invoked without 'new'

🐛 Bug Report

Hi, got some strange error with a basic “Hello world” app.

Class constructor SvelteComponent cannot be invoked without 'new', pointing my app.js

🎛 Configuration (.svelterc, package.json, cli command)

Nothing special.

💻 Code Sample

Everything’s in the repo, but the code is quite simple :

import App from "./components/app.svelte";

const root = new App({
    target: document.querySelector("#root"),
    props: {},
});

export default root;

and the app.svelte is:

<script>
	let name = 'world';
</script>

<h1>Hello {name.toUpperCase()}!</h1>

🌍 Your Environment

Svelte version ^3.1.0, Parcel version ^1.12.3, plugin version 3.0.0

---

Thanks in advance!

[samuelgozi]

This is not an issue specific to this plugin, this is an issue that is caused due to some design decisions made in Parcel. Specifically(as mentioned above) the decision not to transpile packages in the node_modules folder. You can see the issue in their repository here: https://github.com/parcel-bundler/parcel/issues/1655

I’m subscribed to that issue, and to other issues regarding HMR, and will update this plugin when possible. Until then there is nothing we can do… EDIT: Updated the link to the issue, accidentally linked a different one.

[GeordieP]

I have the same issue.

Adding the following to package.json (as recommended by this comment) get things compiling and displaying on the page:

  "browserslist": [
    "last 1 chrome versions"
  ],

However, HMR throws an error (browser console):

proxy.js:62 Uncaught TypeError: Cannot read property 'apply' of undefined
    at proxyComponent.self.<computed> [as get] (proxy.js:62)
    at proxyComponent._rerender (proxy.js:185)
    at hot-api.js:43
    at Array.forEach (<anonymous>)
    at reload (hot-api.js:43)
    at Object.eval (eval at hmrApply (hmr-runtime.js:153), <anonymous>:104:11)
    at newRequire (main.1f19ae8e.js:47)
    at hmrAcceptRun (hmr-runtime.js:203)
    at hmr-runtime.js:60
    at Array.forEach (<anonymous>)

Manually refreshing the page works fine, so we can provide the --no-hmr CLI option to Parcel and get rid of that issue, but obviously this isn’t ideal as we no longer have HMR.