deno syntax episode downloader

download-shows.ts

// deno run --allow-net --allow-write download-shows.ts

import { download } from "https://deno.land/x/download/mod.ts";
const showList = 'https://syntax.fm/api/shows';

async function getShowList(): Promise<Show[]> {
  const list = await (await fetch(showList)).json();
  return list;
}

function generateShowName(show: Show) {
  return `Syntax ${show.number} - ${show.title.replace('/', '')} - ${show.displayDate}.mp3`;
}

async function downloadShow(show: Show) {
  const fileObj = await download(show.url, {
    file: generateShowName(show),
    dir: './shows'
  });
}

async function go() {
  const showList = await getShowList();
  for (const show of showList) {
    console.log(`Downloading show ${generateShowName(show)}`);
    await downloadShow(show);

  }
  console.log('Done!');
}

go();

interface Show {
  number: number;
  title: string;
  date: number;
  url: string;
  slug: string;
  html: string;
  notesFile: string;
  displayDate: string;
  displayNumber: string;
}

add mkdir

// deno run --allow-net --allow-write --allow-read download-shows.ts

// ...

async function downloadShow(show: Show, dir: string) {
  const fileObj = await download(show.url, {
    file: generateShowName(show),
    dir
  })
}

async function mkdir(dir: string) {
  try {
    const fileInfo = await Deno.stat(dir)
  } catch {
    await Deno.mkdir(dir, {mode: 0o755})
  }
}

async function go(dir: string) {
  await mkdir(dir)
  const showList = await getShowList()
  for (const show of showList) {
    console.log(`Downloading show ${generateShowName(show)}`)
    await downloadShow(show, dir)
  }
  console.log('Done!')
}

go('shows')

//...

great stuff :)

My only suggestion would be to optimise the downloads slightly by firing them off all together instead of sequentially:

async function go() {
  const showList = await getShowList();

  const pendingDownloads = showList.map(show => {
    console.log(`Downloading show ${generateShowName(show)}`);
    return downloadShow(show);
  });

  await Promise.all(pendingDownloads);

  console.log('Done!');
}

go();

there are 300 shows, would likely get blocked by the server or download all of them slowly. Not a huge benefit to doing that.

allSettled would be better too, because if 1 show failed, the whole jig is up

good point on the allSettled - haven't had to use it yet to be honest, so doesn't spring to mind!