RFC 001: Improving language support #1159
Conversation
novemberborn
requested review from
sindresorhus,
vadimdemedes and
jamestalmage
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Great, hope we can add support to those languages soon. As my view, if we could get rid of the limitation in ava-files, ie: do not restrict the file extension, just let users define them... Then we can use |
One of the patterns we support is one that matches a directory. AVA automatically expands that to find all
While tempting, I think the performance cost will be too high. It'll probably also stop us from doing things like #789. |
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Thanks for writing this @novemberborn. It's well researched and argued.
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| The above assumes AVA is used with regular JavaScript projects that do not require compilation. Many users though already have a Babel pipeline in place and wish to use AVA without having to precompile their source files. | ||
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| At it's simplest, setting `"babel": true` in the AVA configuration enables AVA's support for Babel projects. Test and helper files are compiled as per the above, but source files are now automatically compiled as well. |
| AVA's handling of Babel projects can be further configured by passing an options object instead of `true`: | ||
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| * `compileSources: true | false`: defaulting to `true`, determines whether sources are compiled. | ||
| * `extensions: "js" | ["js", "jsx", ...]`: defaulting to `"js"`, specifies the allowed file extensions. This expandn the default test file patterns. |
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| `sourceOptions` can be used to extend a shared Babel configuration so that the source files can be loaded in AVA tests. For instance users may [rely on webpack to resolve ES2015 module syntax at build time, but still need to apply `babel-plugin-transform-es2015-modules-commonjs` for sources to work in AVA][source options reason]. | ||
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| `sourceOptions` and `testOptions` may specify `ignore` and `only` values. These are only used to determine whether the file needs compilation. They do not impact test file selection or source watching. |
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It's not immediately clear that ignore and only refers to Babel options.
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| ## Compilation | ||
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| Based on this [proof of concept](https://github.com/avajs/ava/pull/1082) Babel compilation is moved into the test workers. If source files are to be compiled AVA will load its own require hook, rather than relying on `babel-core/register`. |
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| AVA's handling of Babel projects can be further configured by passing an options object instead of `true`: | ||
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| * `compileSources: true | false`: defaulting to `true`, determines whether sources are compiled. |
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So does this mean that compilation of sources are now true by default without any config?
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Only if you set babel. So out of the box the behavior stays exactly the same as it is now (with helper compilation).
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Looks like a good plan to me.
I'm wondering though: For Babel compilation, AVA will probably always stick to the version it's shipped with, and not the version that was installed by the user in their project. I think that's fine as I don't think this has played us tricks as of yet.
But how will TS compilation be made? Will AVA have to ship with the TypeScript build tools? Or can we expect it as an optional peer dependency or something?
We will not bundle TypeScript. Users will have to add TypeScript as a dependency. We'll throw a nice error if they forgot to add the dependency. (It will also not be a package.json |
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We might not even include the TypeScript support module (I think that's what I proposed here, but on mobile so don't feel like checking right now). |
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Great work, @novemberborn! Thorough and to the point! I wonder if we could come up with a better name for |
Yea I hear ya. It's a (no longer documented, as far as I can tell) option in the transform APIs though. It refers both to What's tricky is that the |
Though I haven't spoken with anybody, it seems pretty clear to me that it's Anything else or is this good to go? |
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I shall commence the project planning! 💥 |
An RFC with a proposal for improving AVA's support for Babel, React and TypeScript projects.
We'll leave this open as a PR for a while to gather feedback. If accepted this incorporates / supersedes #707, #1082, #945, #631 and #1122.