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If you're writing a library that needs to work in Node.js and in Browsers, it's quite difficult to figure out what "the right thing" to do with binary is.

If you want to be compatible with Node.js libraries you'll need to accept and return Buffer instances. If you want to be compatible with Browser API's you'll need to accept and return a number of types, the browser is sort of a mess when it comes to binary with many different "views" of binary data.

The moment you use the Node.js Buffer API in a library that is bundled for use in Browsers the bundler will inject a rather large polyfill for the entire Buffer API. It's quite difficult to accept and return Buffer instances while avoiding this penalty.

However, there is some good news. No matter what the binary type there's an underlying ArrayBuffer associated with the instance. There's also one generic binary view object available in both Node.js and Browsers called DataView. This means that you can take any binary type and do a zero memcopy conversion to a DataView.

But there are some problems with DataView. Not all APIs take it in browsers and almost none accept it in Node.js. It's a great API for reading and writing to an ArrayBuffer but it lacks a lot of other functionality that can be difficult to accomplish cross-platform.

bytesish is here to help. This library helps you accept and convert different binary types into a consistent type, DataView, without loading any polyfills or other dependencies, then convert back into an ideal type for the platform your library is running in.

What bytesish does:

  • Returns a DataView from any known binary type (zero copy).
  • Creates a DataView from a string with any encoding.
  • Converts any type to a string of any encoding.
  • Converts any to an ideal native object (Buffer or Uint8Array).
  • Provides utility functions for comparison, sorting, copying and slices any binary type or string.

bytesish does not create a new Binary Type for accessing and manipulating binary data, because you can just use DataView for that. bytesish tries to be a small piece of code that does not contribute any more than necessary to your bundle size. It does this by containing only the binary operations you need that are difficult to do cross-platform (Node.js and Browsers).

let bytes = require('bytesish')
let view = bytes('hello world')
/* zero copy conversions */
view = bytes(Buffer.from('hello world')) // Buffer instance
view = bytes((new TextEncoder()).encode('hello world')) // Uint8Array
/* base64 conversions */
let base64String = bytes.toString(view, 'base64')
base64String = bytes.toString(Buffer.from('hello world'), 'base64')
base64String = bytes.toString('hello world', 'base64')
/* since this is a string conversion it will create a new binary instance */
let viewCopy = bytes(base64String, 'base64')


Zero Copy


bytes.sort(a, b), b)

bytes.native(from[, encoding])

bytes.slice(from[, start=0[, end=from.byteLength]])

bytes.typedArray(from[, Class=Uint8Array])

Optimized (memcopy only when necessary)

bytes.arrayBuffer(from[, encoding])

Memory Copy

All memcopy APIs return an ArrayBuffer

bytes.memcopy(from[, encoding])

Returns an ArrayBuffer copy of the given binary or string.

bytes.memcopySlice(from[, start=0[, end=from.byteLength]])

Returns an ArrayBuffer copy from a slize of the given binary or string.


values is an iterable of binary or string types.

Returns a newly allocated ArrayBuffer contained the concatenated binary data.

String Conversions

bytes(from[, encoding])

bytes.toString(from[, outputEncoding])




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npm i bytesish

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  • mikeal