s3-batch-upload/lib/batch.js

Super fast batched S3 folder uploads from CLI or API.

"use strict";

exports.__esModule = true;
exports.default = streamBatch;

function streamBatch({
  concurrency,
  files,
  processItem,
  onProgress
}) {
  return new Promise(resolve => {
    let count = 0;
    const total = files.length;
    const results = []; // when upload for one item is done, complete or process the next

    const onItemDone = result => {
      results.push(result);
      count += 1; // if completed

      if (!files.length && count === total) {
        // temp fix for https://github.com/visionmedia/node-progress/pull/183
        setTimeout(() => {
          onProgress();
          resolve(results);
        }, 50);
      } else {
        onProgress();

        if (files.length) {
          processItem(files.shift()).then(onItemDone);
        }
      }
    }; // start 'threads'


    for (let i = 0; i < Math.min(concurrency, files.length); i += 1) {
      processItem(files.shift()).then(onItemDone);
    }
  });
}