I was trying to implement a basic hello world Lightning Web Component in the playground using this link in the component library - https://gs0.lightning.force.com/docs/component-library/documentation/lwc/lwc.install_playground but I keep getting this error and I have followed the steps exactly as stated. (copy-paste)

Unable to resolve c-hello-world from root/app

enter image description here

Anybody else tried this yet?


2 Answers 2


Salesforce Developer here. The LWC playground has been fixed. Give it a try!


I had the same issue. When I name my lwc helloWorld (camel case) and reference it in the app html as kebab-case, I get an error in the preview window:

Unable to resolve c-hello-world from root/app

If I change the camel case to all lowercase, and remove the hyphen when referencing it in the app, it works just fine.

I’ve reported.

  • And how would you resolve the problem with the firstName variable? import { LightningElement, api } from 'lwc'; export default class App extends LightningElement { @api firstName; } Feb 18, 2019 at 7:01
  • Because using firstname instead did not work in my case. Feb 18, 2019 at 7:02

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