WeTransfer/wt-js-sdk

const queue = require('async/queue');

const config = require('../../config');
const logger = require('../../config/logger');

module.exports = function({ uploadChunk }) {
  // Create a queue object with a concurrency defined in the configuration.
  // uploadChunk will be executed for every chunk.
  const uploadQueue = queue(uploadChunk, config.concurrency);

  // Checks if we can try to upload the provided chunk
  // based on the number of actual retries and the maximum
  // number of retries per chunk.
  function canRetryUpload(chunk, config) {
    return chunk.retries < config.chunkRetries;
  }

  return function enqueueChunk(chunk) {
    logger.debug(
      `[${chunk.file.name}] Queuing chunk #${chunk.partNumber}. Retry #${chunk.retries}.`
    );

    return uploadQueue
      .pushAsync(chunk)
      .then(() => chunk)
      .catch((error) => {
        logger.debug(
          `[${chunk.file.name}] Chunk #${chunk.partNumber} failed to upload.`
        );

        if (canRetryUpload(chunk, config)) {
          chunk.retries++;
          return enqueueChunk(chunk);
        }

        throw error;
      });
  };
};