Ability to generate .d.ts types file

[holtwick]

I wonder how to use estrella correctly to generate a types file. I've set up a very simple example to show the issue:

https://github.com/holtwick/estrella-ts-module

I would like to add the working result to https://github.com/holtwick/create-estrella

[rsms]

Interesting idea! It would be nice if this was an Estrella build option, like build({ typedefOutput: "dist/foo.d.ts" })

In the meantime I think you could accomplish this by using the typescript API

Something like this:

#!/usr/bin/env node
const { build } = require("estrella")
const pkg = require("./package.json")
const ts = require("typescript")

function generateTypeDefs() {
  const filenames = [ ... ]
  const compilerOptions = { optionsFromTSConfigFile..., declaration: true }
  const program = ts.createProgram(filenames, compilerOptions)
  const emitResult = program.emit()
  // check emitResult.diagnostics and .emittedFiles
}

build({
  bundle: true,
  sourcemap: true,
  format: "esm",
  entry: "src/index.ts",
  outfile: pkg.module,
  onStart: generateTypeDefs,
}) 

[lann]

The best-performing way (probably) to do this would be for tsc to do it while type-checking. I hacked this together by modifying estrella locally; it was a little messy with the current design but it did work.

Edit: I came up with this minimally-invasive change that let me do what I needed with tslint: { args: ['--emitDeclarationOnly', ...] }:

--- a/src/tslint.js
+++ b/src/tslint.js
@@ -107,8 +107,9 @@ export function tslint(options /*:TSLintOptions*/) {
     }
 
     // CLI arguments
+    const noEmit = !(options.args || []).includes('--emitDeclarationOnly');
     let args = [
-      "--noEmit",
+      noEmit && "--noEmit",
       options.colors && "--pretty",
       options.watch && "--watch",
       tsconfigFile && "--project", tsconfigFile,

[holtwick]

Thanks a lot for the example @rsms ❤️

I guess I will wait for an implementation in Estrella then. For now, it seems to be more straight forward to use tsc for dist building directly for such use cases.

[rsms]

Nice @lann! If you'd like to take on adding this "for real" in a PR (preferably with test; I can help you in the PR with this) that would be ace.

[lann]

Sure, I'd be happy to not carry the patch myself. Is the approach alright? Another possibility would be to add a noEmit option that defaults true.

[rsms]

23dcb87 adds an example of how to generate type declaration files.
Try it from source with:

git clone https://github.com/rsms/estrella.git
cd estrella
./test/test.sh examples/typedef-generation

[marcofugaro]

Would be great if this was just an option to estrella!