What is the webpack:// protocol?

[npetruzzelli]

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I originally tried asking this question on StackOverflow, but with no luck. Since the question will likely be deleted, I will copy the contents below:

I downloaded and searched the documentation repository using my text editor for the string webpack://, and found it located in only two documents:

• src/content/configuration/index.md
  • which goes to: https://webpack.js.org/configuration/
• src/content/configuration/output.md
  • which goes to: https://webpack.js.org/configuration/output/

As far as I can tell, this is not an actual protocol, much less one a browser can understand.

Questions:

1. What is the webpack: protocol intended to be used for?
2. Where can I find documentation on it?
3. (assuming it is used internally by webpack or webpack dev server) Why do I see it output in Source Maps or in some project boiler plates, when the browser has no way of understanding what it should do with the protocol?

Update 2018-05-25

I checked Webpack's source code in addition to their documentation repo, and this is what I found:

• https://github.com/webpack/webpack/tree/v4.8.3/examples/source-map/
• lib/EvalDevToolModuleTemplatePlugin.js
• lib/EvalSourceMapDevToolModuleTemplatePlugin.js
• lib/SourceMapDevToolPlugin.js

(Paths instead of links since I lack the reputation to post more than 8)

StackOverflow Comments

I mean that the structure of the source URL in a sourcemap is meaningless to tooling. ie, the protocol doesn't matter. – SLaks May 25 at 15:17

... The protocol shouldn't matter, but for some reason it does, especially when the final sourcemap includes this as a protocol. The browser has no way of understanding a webpack:// URL. It shows up in the links above and in Angular CLI ( github.com/angular/angular-cli/blob/1.7.x/packages/%40angular/… ) when you eject a configuration (I'm currently on 1.7.4, they recently made the jump from 1.x to 6.x, which temporarily removes "eject"). I'd like to know why the webpack and angular teams use it. – nick May 25 at 16:27

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Since Angular CLI also uses/used the webpack:// protocol, is there anyone here who might be able to explain it to me?

Thanks and regards.

[noscripter]

It is a custom protocol used in webpack source map, you can customize it by checking out this doc: https://webpack.js.org/configuration/output/#output-devtoolmodulefilenametemplate

[npetruzzelli]

Thank you for your response. I am already aware that it is configurable.

My goal is to understand what it does for source maps in the context of Webpack. Outside of webpack it is an unknown/invalid URI scheme. I am looking at contributing to a number of existing webpack plugins with the goal of getting source maps to behave in an expected way. Currently, there are scenarios where it does not.

Does the webpack:// scheme have more to do with webpack-dev-server than webpack? How is it used? What does it do behind the scenes?

These are the questions I'm trying to understand as a developer writing software that generates source maps, not as a developer simply using source maps as a debugging tool.

[vanmxpx]

how can i override devtoolModuleFilenameTemplate in angular.json? Since i cannot eject webpack config from angular project i need to rewrite this option in angular.json. This option generate many troubles while debugging in chrome or firefox.

[npetruzzelli]

@vanmxpx - Your problem doesn't seem to be related to the original topic of this issue, you may be better served opening a new issue to get the correct attention on it. You may also find the following helpful:

https://github.com/angular/angular-cli/blob/v6.0.7/docs/documentation/config.md

Though, I don't know if that applies to webpack configuration under the hood.

Since the docs note that eject is temporarily disabled, I imagine they are aware of it and already have an issue open for resolution in the future.

[vanmxpx]

@npetruzzelli I have create the issue, but still quite. Thank you for response and for ng config, might be helpful.

[npetruzzelli]

You're welcome, and good luck!

[alan-agius4]

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