fetch-in-chunks

fetch-in-chunks

A utility for fetching large files in chunks with support for parallel downloads, progress tracking, and request abortion.

Installation

Install the package using npm:

npm install fetch-in-chunks

Usage

Importing the Module

import fetchInChunks from 'fetch-in-chunks';

Function Signature

async function fetchInChunks(
  url,
  chunkSize = 5 * 1024 * 1024,
  maxParallelRequests = 6,
  progressCallback = null,
  signal = null
)

Parameters

• url (string): The URL of the file to download.
• chunkSize (number, optional): The size of each chunk in bytes. Defaults to 5 MB.
• maxParallelRequests (number, optional): The maximum number of parallel chunk requests. Defaults to 6.
• progressCallback (function, optional): A callback function that is called with the downloaded bytes and total file size. signal (AbortSignal, optional): An AbortSignal to allow aborting the request.

Returns

• Promise<Blob>: A promise that resolves to a Blob containing the downloaded file.

Example

Basic Usage

import fetchInChunks from 'fetch-in-chunks';

async function downloadFile() {
  try {
    const blob = await fetchInChunks('https://example.com/largefile.zip');
    // Create a download link and trigger the download
    const url = URL.createObjectURL(blob);
    const a = document.createElement('a');
    a.href = url;
    a.download = 'largefile.zip';
    document.body.appendChild(a);
    a.click();
    URL.revokeObjectURL(url);
  } catch (error) {
    console.error('Error fetching file:', error);
  }
}

downloadFile();

With Progress Callback

import fetchInChunks from 'fetch-in-chunks';

async function downloadFileWithProgress() {
  try {
    const blob = await fetchInChunks(
      'https://example.com/largefile.zip',
      5 * 1024 * 1024,
      6,
      (downloaded, total) => {
        console.log(`Downloaded ${((downloaded / total) * 100).toFixed(2)}%`);
      },
    );
    // Create a download link and trigger the download
    const url = URL.createObjectURL(blob);
    const a = document.createElement('a');
    a.href = url;
    a.download = 'largefile.zip';
    document.body.appendChild(a);
    a.click();
    URL.revokeObjectURL(url);
  } catch (error) {
    console.error('Error fetching file:', error);
  }
}

downloadFileWithProgress();

With AbortController

import fetchInChunks from 'fetch-in-chunks';

async function downloadFileWithAbort() {
  const controller = new AbortController();
  const signal = controller.signal;

  try {
    const blob = await fetchInChunks(
      'https://example.com/largefile.zip',
      5 * 1024 * 1024,
      6,
      (downloaded, total) => {
        console.log(`Downloaded ${((downloaded / total) * 100).toFixed(2)}%`);
      },
      signal,
    );
    // Create a download link and trigger the download
    const url = URL.createObjectURL(blob);
    const a = document.createElement('a');
    a.href = url;
    a.download = 'largefile.zip';
    document.body.appendChild(a);
    a.click();
    URL.revokeObjectURL(url);
  } catch (error) {
    if (error.name === 'AbortError') {
      console.log('Download aborted');
    } else {
      console.error('Error fetching file:', error);
    }
  }
}

// To abort the download at any time
controller.abort();

License

This project is licensed under the Apache 2.0 License. See the LICENSE file for details.