Feature: Loaders API: add method to get outputOptions

[aarefiev]

Feature request

What is the expected behavior?
I would be nice to have ability to get formatted outputOptions like this._compilation.outputOptions but without using structure hacking.

What is motivation or use case for adding/changing the behavior?
I found that some of output options not working as I expected. Some days ago I configured webpack based project with output.hashDigestLength option. But when I set it, only bundled files and files processed by plug-ins are ha truncated names as I expected, but files that processed by loaders only are not.

I did not understand what was wrong, because the documentation says

The lengths of [hash] and [chunkhash] can be specified using [hash:16] (defaults to 20). Alternatively, specify output.hashDigestLength to configure the length globally.

According to documentation all plug-ins has access to outputOptions through Hooks API. But loaders are not. I think it is not good 👎

How should this be implemented in your opinion?
I think in Loaders API should be a method to get formatted outputOptions.

Are you willing to work on this yourself?
yes, sure

[mc-zone]

You can visit this._compilation.outputOptions.hashDigestLength to get this config and the value has been validated. I'm not sure what the exact formatted outputOptions you point is? Could you please provide a mini repo to reproduce your problem?

[aarefiev]

@mc-zone

You can visit this._compilation.outputOptions.hashDigestLength to get this config and the value has been validated

The this._compilation option is hacky access to the Compilation object of webpack. Is there any way to get output options without hacking? I didn't found API method to get.

I'm not sure what the exact formatted outputOptions you point is?

As "formatted" I mean options from compiler after init. Sorry for the wrong explanation.

Could you please provide a mini repo to reproduce your problem?

I sent pr for webpack/loader-utils (webpack/loader-utils#120). As you can see there, I using option from this._compilation object, but as @evilebottnawi says, it is wrong way (https://github.com/webpack/loader-utils/pull/120/files#diff-8e83cc01b69358d1f366c2c32b490456R67).

[alexander-akait]

@mc-zone we need api for this because in future it can be changes, using _* options are hacky

[mc-zone]

@evilebottnawi Oh yes. These _* API has been marked as deprecated for so long.

But AFAIK, this._compilation still exist in webpack 5 and some other main loaders also using it (like the loader part of mini-css-extract-plugin)

It might frequently be used. should we make it public?

[aarefiev]

@mc-zone If that we can create method this.compilation as a reference to this._compilation. If this._compilation will changed in future we can update this.compilation only but without updating loaders.

I can work on it if possible.

[sokra]

this._* is not deprecated, it's private. Loaders can use it on it's own risk. When using it you should expect that the loader breaking on major webpack releases. Basically it's more a plugin than a loader. The public loader API is more stable and probably won't break/change on major releases. It's also not webpack specific so technically you could use it in other things (there is a loader-runner npm package for that).

Exposing outputOptions on the public API would break that assumption, as outputOptions is pretty webpack-specific and may change between versions. So if we would expose it, it would probably exposed as this._outputOptions. And this won't have a benefit over this._compilation.outputOptions.

[sokra]

So: Use this._compilation.outputOptions and add the supported webpack versions as peerDependencies.

[alexander-akait]

@sokra we need this in loader-utils, they are used in many loaders/plugins and will be great do stable api, without private access to avoid breaking between difference webpack version

[aarefiev]

@sokra what about making this._compilation public? Is there any reason not to do this?

[alexander-akait]

/cc @aarefiev friendly ping, we can implement getHashOutputOptions and return all hash* options from compilation. No need to make the compilation public.

[aarefiev]

@evilebottnawi thanks

[webpack-bot]

This issue had no activity for at least half a year.

It's subject to automatic issue closing if there is no activity in the next 15 days.

[alexander-akait]

Bump

[webpack-bot]

This issue had no activity for at least three months.

It's subject to automatic issue closing if there is no activity in the next 15 days.

[alexander-akait]

Bump

[webpack-bot]

Issue was closed because of inactivity.

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