How to wait for a stream to finish piping? (Nodejs)

Question

I have a for loop array of promises, so I used Promise.all to go through them and called then afterwards.

let promises = [];
promises.push(promise1);
promise         


        

Answer 1

You can write the else part inside a self invoked function. So that the handling of stream will happen in parallel

(function(i) {
    let file = fs.createWriteStream('./hello.pdf');
    let stream = responses[i].pipe(file);
  /*
     I WANT THE PIPING AND THE FOLLOWING CODE 
     TO RUN BEFORE NEXT ITERATION OF FOR LOOP
  */
    stream.on('finish', () => {
      //extract the text out of the pdf
      extract(filePath, {splitPages: false}, (err, text) => {
      if (err) {
        console.log(err);
      } 
      else {
        arrayOfDocuments[i].text_contents = text;
      }
    });
  });    
})(i) 

Else you can handle the streaming part as part of the original/individual promise itself.

As of now you are creating the promise and adding it to array, instead of that you add promise.then to the array(which is also a promise). And inside the handler to then you do your streaming stuff.