DevTools option to allow local Source overrides

[flipclone]

I'm sure any developer reading this is familiar with Chrome's feature to allow local Source overrides while the devtools window is open.

I'm not sure if Firefox's 'source map' feature can accomplish this same task with local files.

[Jon]

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[Honza]

Yes, local source overrides is a feature that will most likely be on our roadmap for 2023

> I'm not sure if Firefox's 'source map' feature can accomplish this same task with local files.

Currently no, but I'd be curious what are your thoughts? Do you have more details about how this could work?

[flipclone]

I'm not a dev so I dont know how anything works, I barely know how to use tools that I play with.

I dont fully understand source mapping and I've never used it, but from what I've read, if source mapping is implemented you can use it to download the source files for debugging, but how can you debug if there is no way to make your changes visible in the browser? Unless I am completely misunderstanding what source mapping is supposed to do, which wouldnt surprise me.

[JS00001]

Add Network Overrides, Same as Chrome

Chrome has the ability to right click a network request, and 'Override Content', IE you can modify a response from a server for testing. This is already very helpful for chrome, would be nice in Firefox too

[Jon]

Thanks for submitting an idea to the Mozilla Connect community! Your idea is now open to votes (aka kudos) and comments.

[thomassth]

>Yes, local source overrides is a feature that will most likely be on our roadmap for 2023

Is it still in your 2025 road map?

[stripTM]

Here is the docuentation overrides in Chrome, it seems to me a very useful feature in cases where you don't have access to the backend or you don't want to deploy.

[avgustine]

Would love to have it in FF !

[agusagungsantos]

Any update regarding devtool override in mozzila? Would love to see the feature

[Honza]

Enhancing the support for local files override is on our 2025 Roadmap

Currently, local file override support is available in the Debugger panel. To use it, you can right-click on a source file, choose "Add script override," and select a local JavaScript file to replace the one downloaded from the server.

Planned enhancements will expand this functionality to the Network panel, enabling the override of any server-side resource—not just JavaScript files.

[petoknm]

@HonzaCan you provide any further documentation of this feature?

I am unable to get it to work, so I want to make sure I am following the right steps. I managed to get the purple dot signaling an override, but my local file, which I edited, is not being used.

[Honza]

You can check this thread for more info

https://connect.mozilla.org/t5/ideas/devtools-option-to-allow-local-source-overrides/idi-p/18330

[Jon]

(Note: similar ideas have been merged into this thread)