Angular builds with @angular/service-worker creates incorrect hashes

[hpieterse]

Description

With an Angular project using @ngx-env/builder:

• when using @angular/service-worker to add service worker support, and
• replacing something in the index.html from an environment variable,
• a build generated a ngsw.json file with incorrect hashes.

Example

Here is an minimal example
https://stackblitz.com/edit/ngx-env-dht6lfds

To reproduce the issue:

1. run npm run build

2. check the hash of the index.html file using:

shasum ./dist/demo/browser/index.html

(this command is not available in StackBlitz, so you will have to download the file locally)

3. Compare this to the hash in dist/demo/browser/ngsw.json

Cause

This was probably introduced in this PR #108. in packages/angular/src/builders/browser/index.ts the index.html file is changed after the build, which is probably after the service worker hashes where generated.

Workaround

As a workaround (if someone with the same problem happens finds this issue) you can re-calculate the hashes using something like this:

npx ngsw-config dist/demo/browser/ ngsw-config.json