lvin•2y ago

not sure why this code is erroring

for (const number of genNumbers()) {
  const result = await fetchPages(number);
  if (result instanceof Error) break;
  const urls = parse(result);
  await Promise.all(
    urls.map((url) =>
      fetchPage(`https://test.nl${url}`).then(({ name, videos }) =>
        Deno.writeTextFile(name, JSON.stringify(videos))
      )
    )
  );
}

for (const number of genNumbers()) {
  const result = await fetchPages(number);
  if (result instanceof Error) break;
  const urls = parse(result);
  await Promise.all(
    urls.map((url) =>
      fetchPage(`https://test.nl${url}`).then(({ name, videos }) =>
        Deno.writeTextFile(name, JSON.stringify(videos))
      )
    )
  );
}

Task generate deno run -A ./scripts/generate.ts
error: Uncaught TypeError: Expected string at position 1
        Deno.writeTextFile(name, JSON.stringify(videos))
             ^
    at writeFile (ext:deno_fs/30_fs.js:807:18)
    at Object.writeTextFile (ext:deno_fs/30_fs.js:850:12)
    at file:///home/al/Code/crookedy/scripts/generate.ts:76:14
    at eventLoopTick (ext:core/01_core.js:183:11)
    at async Promise.all (index 10)
    at async file:///home/al/Code/crookedy/scripts/generate.ts:73:3

Task generate deno run -A ./scripts/generate.ts
error: Uncaught TypeError: Expected string at position 1
        Deno.writeTextFile(name, JSON.stringify(videos))
             ^
    at writeFile (ext:deno_fs/30_fs.js:807:18)
    at Object.writeTextFile (ext:deno_fs/30_fs.js:850:12)
    at file:///home/al/Code/crookedy/scripts/generate.ts:76:14
    at eventLoopTick (ext:core/01_core.js:183:11)
    at async Promise.all (index 10)
    at async file:///home/al/Code/crookedy/scripts/generate.ts:73:3

9 Replies

Fifth-Normal-Form•2y ago

may have to await the parse(result)?

lvinOP•2y ago

no that function is synchrous, and using writeTextFileSync doesn't help either

Esente•2y ago

Can you check if you actually get a string for name? The error says that the first argument for writeTextFile is not a string.

lvinOP•2y ago

horrible error message

Mr.Possumz•2y ago

If Promise.all() is expecting an iterable of promises, technically what you're returning is a composition of a promise and a chained statement. I don't often use Promise.all but I'm betting that fetchPage is generating the promise and passing the promise to the chained .then() statement, which fails to destructure the name and videos variables. You probably just need to declare the map callback as async to generate a promise.

lvinOP•2y ago

nah, functions only need to be tagged w/ async if im using await inside them. the map converts all the urls Array<string> to Array<Promise<{name:string,videos:Array<Video>}>> hence why i can use promise.all with it the name parameter for Deno.writefile was undefined instead of a string so thats why shit borked

Kyiro•2y ago

console log videos

NeTT•2y ago

That was a poor error message indeed. Might need to open an issue for enhancement.

ybabts•2y ago

It would be helpful to share the functions you're using inside your snippet. Whatever object you're destructuring in the then statement, the name property isn't always a string, hence the error. You should log the output of the object you're destructuring to confirm this. The solution would be to type check name and videos to ensure that they are the proper types before attempting to write them to a file. Also I am interested in what this is here

const result = await fetchPages(number);
if (result instanceof Error) break;

const result = await fetchPages(number);
if (result instanceof Error) break;