const downloadurl = ['url1', 'url2']
const filename = 'run.jar'

downloadurl.forEach((urls) => {
    https.get(urls, (httpsres) => {
        const path = `${installationdirectory}/${filename}`
        const filePath = fs.createWriteStream(path);
        httpsres.pipe(filePath);
        filePath.on('finish',() => {

            filePath.close();
            const filesize = fs.statSync(path).size
            // Verify if the size of the file is smaller than 1Kb
            if((filesize / 1024) < 1) return;

            // Want to skip this console.log if the file size is smaller than 1Kb and try with the other downloadurl (Hence why the downloadurl.forEach)
            console.log('File downloaded!'); 


        })
    })
})

Basically, I'm using the https module from NodeJS which doesn't give an error if the download url doesn't exist, as it just creates a 1-byte file with the run.jar name instead. So, I want to make it stop executing code and try to download with the other URL if the size of the file is smaller than 1Kb, any ideas?

CodePudding user response：

1. you can use every() loop. and when you want to break the loop just don't return anything.

// Prints "1, 2, 3"
[1, 2, 3, 4, 5].every(v => {
  if (v > 3) {
    return false;
  }

  console.log(v);
  // Make sure you return true. If you don't return a value, `every()` will stop.
  return true;
});

2. or you can change length of array using third

const myNums = [1, 2, 3, 4, 5];
myNums.forEach((v, index, arr) => {
  console.log(v);
  if (val > 3) {
    arr.length = index   1; // Behaves like `break`
  }
}

CodePudding user response：

If using a callback structure, as you are at the moment, you could try a recursive function to try further downloads.

function tryDownload(downloadUrls):
    // try download the first
    https.get(downloadUrls[0], (res) => {
        // read it, etc
        // ...

        // if too small, try the next urls
        if ((filesize / 1024) < 1)
            tryDownload(downloadUrls.slice(1));
        else
            // success!
            // ...
    })

You may find it clear to restructure this as an asynchronous function, though. In pseudocode:

    for each url in download urls
        res = await download url
        if res indicates success
            handle the res
            return