Migrating `Deno.run` to `Deno.command` with `readlines`

I had the following:

 browserProcess = Deno.run({
  cmd: buildArgs, // eg chrome exe path, then options
  stderr: "piped",
  stdout: "piped",
});
for await (const line of readLines(browserProcess.stderr!)) {

 browserProcess = Deno.run({
  cmd: buildArgs, // eg chrome exe path, then options
  stderr: "piped",
  stdout: "piped",
});
for await (const line of readLines(browserProcess.stderr!)) {

Now i'm wondering what the best way to do this with Deno.command is?

15 Replies

crowlKats•12mo ago

child.readable.pipeThrough(new TextLineStream()) child being command.spawn() and TextLineStream from https://deno.land/std@0.198.0/streams/mod.ts?s=TextLineStream

Ed, Edd n Eddy•12mo ago

🙏 thanks 🙂 been like 2+ years since ive touched deno so a lot has changed and not familiar with it all

crowlKats•12mo ago

not that long, right 🤔 its been a while, but cant be 2 years

Ed, Edd n Eddy•12mo ago

i dont think i touched deno/drashland shortly after my new job which was 2 years and one month ago so oculd be 1y 10m, though maybe i stopped later than i thought good to see your face though 😛

crowlKats•12mo ago

yea same! I saw you every now and then in destiny's channel talking with Okku, but its been a while since that as well

Ed, Edd n Eddy•12mo ago

was excited to see where destiny went, but wanna get back into deno again although: error: TS2339 [ERROR]: Property 'readable' does not exist on type 'ChildProcess'., deno v1.36.1, windows

crowlKats•12mo ago

ah whoops stdout

Ed, Edd n Eddy•12mo ago

still

Argument of type 'TextLineStream' is not assignable to parameter of type '{ writable: WritableStream<Uint8Array>; readable: ReadableStream<string>; }'.
  Types of property 'writable' are incompatible.
    Type 'WritableStream<string>' is not assignable to type 'WritableStream<Uint8Array>'.
      Type 'string' is not assignable to type 'Uint8Array'.deno-ts(2345)

Argument of type 'TextLineStream' is not assignable to parameter of type '{ writable: WritableStream<Uint8Array>; readable: ReadableStream<string>; }'.
  Types of property 'writable' are incompatible.
    Type 'WritableStream<string>' is not assignable to type 'WritableStream<Uint8Array>'.
      Type 'string' is not assignable to type 'Uint8Array'.deno-ts(2345)

crowlKats•12mo ago

Ah, first you have to pipe through a TextDecoderStream (built-in)

Ed, Edd n Eddy•12mo ago

gotcha

crowlKats•12mo ago

And then through the line stream

Ed, Edd n Eddy•12mo ago

confused, where am i using TextLineStream?

const a = browserProcess.stdout.pipeThrough(new TextDecoderStream)
const b = browserProcess.stdout.pipeThrough(a);

const a = browserProcess.stdout.pipeThrough(new TextDecoderStream)
const b = browserProcess.stdout.pipeThrough(a);

~~oh it hink i see~~

crowlKats•12mo ago

browserProcess.stdout.pipeThrough(new TextDecoderStream()).pipeThrough(new TextLineStream())

Ed, Edd n Eddy•12mo ago

Thanks 🙏 dont suppose you'd know the ChildProcess equivelent of

this.#browser_process.stderr!.close();
this.#browser_process.stdout!.close();
this.#browser_process.close();

this.#browser_process.stderr!.close();
this.#browser_process.stdout!.close();
this.#browser_process.close();

? Tried the ai helper and got:

const stdoutReader = readerFromStreamReader(this.#browser_process.stdout.getReader())
await readAll(stdoutReader)
console.log(1)
const stderrReader = readerFromStreamReader(this.#browser_process.stderr.getReader())
await readAll(stderrReader)
this.#browser_process.kill("SIGINT")

const stdoutReader = readerFromStreamReader(this.#browser_process.stdout.getReader())
await readAll(stdoutReader)
console.log(1)
const stderrReader = readerFromStreamReader(this.#browser_process.stderr.getReader())
await readAll(stderrReader)
this.#browser_process.kill("SIGINT")

but it hangs on line 2 nvm got it sorted

wobsoriano•11mo ago

Hey @ededdneddy9188, do you have an example of your conversion of this? I tried this but it exits immediately https://discord.com/channels/684898665143206084/1131635673217118248/1149868174678958110