Why use babel with typescript?

[pkieltyka]

Hey guys,

Thanks for the thorough blog post. What I'm trying to understand is: why use babel at all with typescript? the tsc is quite good and will only get better, and Babel 6/7 do not support the full TS language.

[damassi]

Hi @pkieltyka - This is a good question!

The reason is due to existing project infrastructure. If starting a project from scratch we would most certainly stick with tsc and go from there, but a lot of our codebases are somewhat old and have complex build pipelines. What Babel 7 + TypeScript support brings to the table is the ability to seamlessly merge old and new tech with very little fuss. For example soon, once Babel 7 stabalizes a bit, we'll be able to set it up in Positron and then import in components from our shared web repo Reaction directly, rather than having to pre-compile into dist and then pull from there. Another side plus is that with noEmit set to false we can lean on some of the advanced caching options available inside of Babel and Webpack leading to really fast recompiles since all that's happening on the tsc side is typechecking.

[alloy]

We use some babel plugins that are quite essential to our code-bases, such as the Relay and styled-components ones. This means that we needed to have a pipeline like tsc -> babel -> js. Especially during development this can be quite costly (parse & generate code twice) and can be tedious to setup and maintain.

Even if we’d really wanted to (but I don’t think we’d want to), tsc has no plugin support at the moment, so being able to build TS code all within Babel is a win in that regard.

Babel indeed doesn’t support namespaces and const enums, but haven’t really had a need for that.

[pkieltyka]

Thanks for the reply guys. That makes sense. I am starting a project from scratch and going to use just tsc but I have the feeling eventually I’ll miss out on features Babel has such as tree shaking. I’m pretty sure tsc doesn’t have tree shaking and neither a way to make it work with async module loading for browsers, but I am sure it will support it someday. Btw, I also use styled components and there is a typescript plugin that works very well with plain tsc.

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On Dec 21, 2017, at 6:37 PM, Eloy Durán ***@***.***> wrote: We use some babel plugins that are quite essential, such as the Relay and styled-components one. This means that we needed to have a pipeline like tsc -> babel -> js. Especially during development this can be quite costly (parse & generate code twice) and can be tedious to setup and maintain. Even if we’d really wanted to (but I don’t think we’d want to), tsc has no plugin support at the moment, so being able to build TS code all within Babel is a win in that regard. Babel indeed doesn’t support namespaces and const enums, but haven’t really had a need for that. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub, or mute the thread.