Angular app doesn't work on Firefox after updating it to Version 8

Question

We have updated an Angular app from version 7.2 to version 8. The update process has worked so far and the app can be used locally and in prod mode (on the server) on Chrome, Firefox Developer Edition, Safari, Opera as usual.

But in the normal Firefox browser and Waterfox, the app does not work:

• The app tries to render while the browser shows the status "Performing a tls handshake to localhost", until at some point a "The connection has timed out" comes.
• In prod mode, after I have deployed the app, at least the login mask shows up but the performance of the app is so bad that hardly nothing works.

We have created a browserlist file with the following content:

# This file is used by the build system to adjust CSS and JS output to support the specified browsers below.
# For additional information regarding the format and rule options, please see:
# https://github.com/browserslist/browserslist#queries

# You can see what browsers were selected by your queries by running:
# npx browserslist

> 0.5%
last 2 versions
Firefox ESR
not dead
not IE 9-11 # For IE 9-11 support, remove 'not'.

Our tsconfig looks like this:

{
  "compileOnSave": false,
  "compilerOptions": {
    "downlevelIteration": true,
    "importHelpers": true,
    "outDir": "./dist/out-tsc",
    "baseUrl": "src",
    "sourceMap": true,
    "declaration": false,
    "moduleResolution": "node",
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "target": "es2015",
    "typeRoots": [
      "Node_modules / @ types"
    ]
    "lib": [
      "ES2016"
      "Dom"
    ]
    "module": "esnext"
  }
}

And the area with the ssl configuration inside the angular.json so:

  "serve": {
    "builder": "@angular-devkit/build-angular:dev-server",
    "options": {
      "browserTarget": "farm-management-ui:build",
      "port": 8080,
      "ssl": true,
      "proxyConfig": "src/proxy.conf.js"
    },

We have already successfully executed the following commands:

ng update @ angular / cli --from 7 --to 8 --migrate - only

ng update @ angular / core - from 7 - to 8 --migrate-only

And I have the feeling that if the app is running in Firefox an endless loop is created, because I can't also open other webpages like Stackoverflow and so on..

Why does Firefox suddenly have this behavior and how can we fix this?

Answer 1

Changing in tsconfig.json the property target from es2015 to old value es5, application works.