Pass in custom chromium prefs (enable developer mode by default)

[aklinker1]

Is this a feature request or a bug?

Feature request.

What is the current behavior?

Currently, web-ext uses chrome-launcher@0.15.1, but v1.1.0 was just released, with a fix to make the prefs option work. This enables us to set custom preferences for the profile, including extensions.ui.developer_mode, which would enable developer mode by default when using web-ext, which is super convenient during development.

import { launch } from 'chrome-launcher';

launch({
  prefs: {
    extensions: {
      ui: {
        developer_mode: true,
      },
    },
  },
});

What is the expected or desired behavior?

Just like the --pref for firefox, it would be awesome if we could add --chromium-pref to the CLI and chromiumPrefs to the JS API. Or at least enable extensions.ui.developer_mode by default. I always have to toggle the setting when developing an extension before debugging the background in chrome.

This might also be a solution for #2874.

I'd be happy to submit a PR, but I can't get tests to pass after upgrading chrome-launcher, there's a error with the watcher that I can't figure out :/

Version information (for bug reports)

• Firefox version: deved 119.0b2
• Your OS and version: MacOS Ventura 13.4.1c
• Paste the output of these commands:

v18.16.1
9.5.1 
7.8.0

[Rob--W]

Neat. I am supportive of setting this flag by default.

If you have something almost working, you could also create a PR and ask for feedback.

[aklinker1]

Nice, I wanted to make sure this was something that would be accepted before I put any more work into it. I'll open a PR sometime soon.

[aklinker1]

@Rob--W I got the tests working! PR opened.