TypeScript icon, indicating that this package has built-in type declarations

2.1.9 • Public • Published


NPM Version npm GitHub Actions Build Windows Build Status Join the chat at FOSSA Status

A simple http file downloader for node.js


  • No thirdparty dependecies
  • Pause/Resume
  • Retry on fail
  • Supports http/https
  • Supports http redirects
  • Supports pipes
  • Custom native http request options
  • Usable on vanilla nodejs, electron, nwjs
  • Progress stats


$ npm install --save node-downloader-helper


For a more complete example check example folder

const { DownloaderHelper } = require('node-downloader-helper');
const dl = new DownloaderHelper('', __dirname);

dl.on('end', () => console.log('Download Completed'));
dl.on('error', (err) => console.log('Download Failed', err));
dl.start().catch(err => console.error(err));

IMPORTANT NOTE: I highly recommend to use both .on('error') and .start().catch, although they do the same thing, if on('error') is not defined, an error will be thrown when the error event is emitted and not listing, this is because EventEmitter is designed to throw an unhandled error event error if not been listened and is too late to change it now.


This can be used as standalone CLI downloader

Install npm i -g node-downloader-helper

Usage: ndh [folder] [url]

$ ndh ./folder http://url


Download Helper constructor also allow a 3rd parameter to set some options constructor(url, destinationFolder, options), these are the default values

    body: null, //  Request body, can be any, string, object, etc.
    method: 'GET', // Request Method Verb
    headers: {},  // Custom HTTP Header ex: Authorization, User-Agent
    timeout: -1, // Request timeout in milliseconds (-1 use default), is the equivalent of 'httpRequestOptions: { timeout: value }' (also applied to https)
    metadata: {}, // custom metadata for the user retrieve later (default:null)
    resumeOnIncomplete: true, // Resume download if the file is incomplete (set false if using any pipe that modifies the file)
    resumeOnIncompleteMaxRetry: 5, // Max retry when resumeOnIncomplete is true
    resumeIfFileExists: false, // it will resume if a file already exists and is not completed, you might want to set removeOnStop and removeOnFail to false. If you used pipe for compression it will produce corrupted files
    fileName: string|cb(fileName, filePath, contentType)|{name, ext}, // Custom filename when saved
    retry: false, // { maxRetries: number, delay: number in ms } or false to disable (default)
    forceResume: false, // If the server does not return the "accept-ranges" header, can be force if it does support it
    removeOnStop: true, // remove the file when is stopped (default:true)
    removeOnFail: true, // remove the file when fail (default:true)
    progressThrottle: 1000, // interval time of the 'progress.throttled' event will be emitted
    override: boolean|{skip, skipSmaller}, // Behavior when local file already exists
    httpRequestOptions: {}, // Override the http request options  
    httpsRequestOptions: {}, // Override the https request options, ex: to add SSL Certs

for body you can provide any parameter accepted by http.request write function req.write(body), when using this, you might need to add the content-length and content-type header in addition with the http method POST or PUT


const data = JSON.stringify({
  todo: 'Buy the milk'
const dl = new DownloaderHelper('my_url', __dirname, { 
method: 'POST',
body: data,
headers: {
    'Content-Type': 'application/json',
    'Content-Length': data.length
} } );

for fileName you can provide 3 types of parameter

  • string: will use the full string as the filename including extension
  • callback(fileName, filePath, contentType): must return an string, only sync function are supported ex: (fileName) => 'PREFIX_' + fileName;, contentType will be provided if available
  • object: this object must contain a name attribute and an optional ext attribute, the ext attribute can be an string without dot(.) or a boolean where true use the name as full file name (same as just giving an string to the fileName parameter) or false (default) will only replace the name and keep the original extension, for example if the original name is and the option is {name: 'somename'} the output will be

for override you can provide 2 types of parameter

  • boolean: true to override existing local file, false to append '(number)' to new file name
  • object: object with properties skip (boolean): whether to skip download if file exists, and skipSmaller (boolean): whether to skip download if file exists but is smaller. Both default to false, for the equivalent of override: true.

for httpRequestOptions the available options are detailed in here

for httpsRequestOptions the available options are detailed in here


Name Description
start starts the downloading
pause pause the downloading
resume resume the downloading if supported, if not it will start from the beginning
stop stop the downloading and remove the file
pipe readable.pipe(stream.Readable, options) : stream.Readable
unpipe (stream) if not stream is not specified, then all pipes are detached.
updateOptions (options, url) updates the options, can be use on pause/resume events
getStats returns stats from the current download, these are the same stats sent via progress event
getTotalSize gets the total file size from the server
getDownloadPath gets the full path where the file will be downloaded (available after the start phase)
isResumable return true/false if the download can be resumable (available after the start phase)
getResumeState Get the state required to resume the download after restart. This state can be passed back to resumeFromFile() to resume a download
resumeFromFile resumeFromFile(filePath?: string, state?: IResumeState) Resume the download from a previous file path, if the state is not provided it will try to fetch from the information the headers and filePath, @see resumeIfFileExists option

usage of resumeFromFile

const downloadDir = 'D:/TEMP';
const { DownloaderHelper } = require('node-downloader-helper');
const dl = new DownloaderHelper('', downloadDir);
dl.on('end', () => console.log('Download Completed'));
dl.on('error', (err) => console.log('Download Failed', err));

// option 1
const prevFilePath = `${downloadDir}/1Gb.dat`;
dl.resumeFromFile(prevFilePath).catch(err => console.error(err));

// option 2
const prevState = dl.getResumeState(); // this should be stored in a file, localStorage, db, etc in a previous process for example on 'stop'
dl.resumeFromFile(prevState.filePath, prevState).catch(err => console.error(err));


Name Description
start Emitted when the .start method is called
skip Emitted when the download is skipped because the file already exists
download Emitted when the download starts callback(downloadInfo)
progress Emitted every time gets data from the server callback(stats)
progress.throttled The same as progress but emits every 1 second while is downloading callback(stats)
retry Emitted when the download fails and retry is enabled callback(attempt, retryOpts, err)
end Emitted when the downloading has finished callback(downloadInfo)
error Emitted when there is any error callback(error)
timeout Emitted when the underlying socket times out from inactivity.
pause Emitted when the .pause method is called
stop Emitted when the .stop method is called
resume Emitted when the .resume method is called callback(isResume)
renamed Emitted when '(number)' is appended to the end of file, this requires override:false opt, callback(filePaths)
redirected Emitted when an url redirect happened callback(newUrl, oldUrl) NOTE: this will be triggered during getTotalSize() as well
stateChanged Emitted when the state changes callback(state)
warning Emitted when an error occurs that was not thrown intentionally callback(err: Error)

event skip skipInfo object

    totalSize:, // total file size got from the server (will be set as 'null' if content-length header is not available)
    fileName:, // original file name
    filePath:, // original path name
    downloadedSize:, // the downloaded amount

event download downloadInfo object

    totalSize:, // total file size got from the server (will be set as 'null' if content-length header is not available)
    fileName:, // assigned name
    filePath:, // download path
    isResumed:, // if the download is a resume,
    downloadedSize:, // the downloaded amount (only if is resumed otherwise always 0)

event progress or progress.throttled stats object

    name:, // file name
    total:, // total size that needs to be downloaded in bytes, (will be set as 'null' if content-length header is not available)
    downloaded:, // downloaded size in bytes
    progress:, // progress porcentage 0-100%, (will be set as 0 if total is null)
    speed: // download speed in bytes

event end downloadInfo object

    totalSize:, // total file size got from the server, (will be set as 'null' if content-length header is not available)
    incomplete:, // true/false if the download endend but still incomplete, set as 'false' if totalSize is null
    onDiskSize, // total size of file on the disk
    downloadedSize:, // the total size downloaded

event renamed filePaths object

    path:, // modified path name
    fileName:, // modified file name
    prevPath:, // original path name
    prevFileName:, // original file name

event error error object

    message:, // Error message
    status:, // Http status response if available
    body:, // Http body response if available


Name Value


$ npm test


Read License for more licensing information.

FOSSA Status


Read here for more information.


  • Better code testing

Package Sidebar


npm i node-downloader-helper

Weekly Downloads






Unpacked Size

47.7 kB

Total Files


Last publish


  • hgouveia