[ironmagma]

Can the configuration have strong types (via TypeScript or similar) pretty pretty please? One of my main frustrations with webpack is the undocumented, unpredictable, unspecified config file format that seems to have no rhyme or reason, which you must often change with every new plugin you add.

[devongovett]

Yep! I think we should be able to publish a JSON schema definition that editors like vscode can use to provide autocomplete etc.

[orf]

That’s not strong typing, that’s automated (and not necessarily up to date) documentation :(

[devongovett]

Is there another way to provide strong types for a JSON file?

I believe vscode uses schemas from http://schemastore.org/ for many config files already.

[orta]

Yep, a schema would work fine for this (and you can generate it from types)

You can test them locally using vscode using the "$schema" field on the root obj, here's an example PR doing all that: https://github.com/danger/peril/pull/281

You can either have users add that schema reference in the JSON (throw it in the template) or ship a vscode extension which connects them

[ironmagma]

If you define the types in TS, you can use https://github.com/YousefED/typescript-json-schema to automatically generate a JSON schema from it. That way, configurations can be specified either in an executable JS module or in a JSON file.

[devongovett]

Yep, we’ll definitely use a tool like that. We already have types in Flow for all of Parcel 2, so should be possible to do something similar.

[orf]

It wasn't clear until now that the configuration is done through JSON rather than being configurable through code (i.e TypeScript).

Urgh, JSON for configuration. That's going to be horrible.

[devongovett]

JSON is much more static and predictable for configuration. Config through a real programming language was a mistake that many tools made unfortunately. Static configuration has several nice properties including cacheability and simplicity that cannot be guaranteed in a full programming language. Just look at webpack.config.js for an example of the opposite.

[manigandham]

All configuration is static. The advantage of using JS (or a language file) is that you run it to generate the appropriate config for that moment and environment.

That need won't ever go away, so not supporting means we're back to users generating their own "static" config files in a separate process. Nothing has been saved, only made more complicated.

[orf]

That's all totally awesome and cool, right up until the moment you want to add a comment to your configuration. Because you know, it's configuration, and that requires comments.

Quite a few tools went from just JSON configuration files to supporting both .js and .json.

Regarding caching, perhaps I'm mistaken but what's the issue there? Two JSON documents can be equivalent with different bytes so you need to re-parse the configuration file fairly often anyway. So what's the difference with just re-evaluating a .js configuration file and caching the output? If someone wants to put a `if (random() > 0.1)` statement in their config then that's their problem.

[Sawamara]

I feel that pain, yeah. On the other hand, at least the error messages are often helpful with Webpack.