Transpiling deno-flavored-typescript

[mhanuszh]

There is no easy to use, zero config way to transpile deno-flavored-typescript to Javascript.

From the TS side:
The typescript that Deno uses is not compatible with the official version (.ts extension, URL imports, etc), so the official tsc is out of the question.

On the Deno side:
Deno has an official tool called deno bundle which works flawlessly. I only have one problem with it: it bundles. Also, its going away in the near future.

My question is:
Are there any plans on adding a built in method for transpiling Typescript (or even JSX 👀) to Javascript? Someting like deno transpile that, unlike deno bundle, would only have one responsibility.

I believe that this is one of the last components that Deno needs to be completely Batteries Includedᵀᴹ

[dsherret]

Are there any plans on adding a built in method for transpiling Typescript (or even JSX 👀) to Javascript? Someting like deno transpile that, unlike deno bundle, would only have one responsibility.

See https://github.com/denoland/deno_emit/blob/main/js/README.md#transpiling

The typescript that Deno uses is not compatible with the official version (.ts extension, URL imports, etc), so the official tsc is out of the question.

For just transpiling a single module, that doesn't involve module resolution, so you can use tsc. There is the ts.transpileModule function in the ts compiler api. That accepts some transforms which could potentially be used to even modify the module specifiers.

[mhanuszh]

Thank you for the tooling suggestions, although my original pain point is the lack of zero config / zero dependency solution.

Yes, I know about the emit module and that tsc can be forced to behave, or even using complete build tools, but these things won't come close to the simplicity of deno bundle utils.ts utils.js

As deno bundle is rightfully deprecated (#11073, #15463), and even if deno pack is taking it's place, I believe that there is a need for a simple, built in way to transpile modules, without bundling them.

My current project includes a few util modules that are used in both the front- and back-end (Deno and the Browser). These modules are themselves separated to other modules and include references to each other and to external sources (esm.sh). I think this is not an uncommon scenario.

The greatest selling point of Deno (at least for me) is the strong "sane defaults for no config, built in tools for no dependencies" ideology. Having to use another module/tool/script for a (in my opinion) fundamental action (turning ts to js) is somewhat does not fit in with those values. Please make the complex simple.

[bartlomieju]

I suggested to add deno transpile subcommand in internal discussions several times, but there was no support from the team. It's about 100 lines of Rust code to add, since we just need to pipe a few existing pieces together. Keep in mind that besides stripping types and performing JSX transforms there would be no changes to the source code (eg. the import specifiers would still reference .ts files).

[dsherret]

This one has been discussed a lot before so going to close. See #14461

There are many ways to transpile and many expected outcomes so this is best left to an external tool. For example, the scenario you described is not supported by the internal transpiler.