javascript-binary-converter

javascript-binary-converter is a simple utility to convert various binary data objects in Javascript, like Blob, File, TypedArray and others. Works both in the browser and in Node.js(with limitations)

If you encounter any bugs or have a question, please don't hesitate to open an issue.

Installation

$ npm install javascript-binary-converter

Usage in the browser, or under any ES6 modules environment:

import converter from "javascript-binary-converter";

Usage in Node.js:

const converter = require("javascript-binary-converter").default;

Usage in the browser, in a classical HTML page:

<script type="module">
  import converter from "/node_modules/javascript-binary-converter/build/esm/index.js";
  ...
</script>

Table of Contents

• Concept
• Usage in Node
• Examples
  • File to Image
  • File to bytes
  • Blob to Image
  • Image to Uint8Array
  • Image to bytes
  • Uint8Array to Image

Concept

converter is a function that accepts any of the convertable objects, recognize the type, and expose the conversion methods that exist for this specific object. Just pass the object you want to convert, and call the appropriate method.

Usage in Node

Not all conversion functionality is available in Node, due to natural limitations. For instance, Image conversion is unavailable, because this object simply doesn't exist in Node(same goes for the File object). The program will throw an exception in these cases. If, for some reason, you need to convert a Blob object(available in Node since version 15) to some other type, import BlobConverter directly, instead of using the generic converter function, which will show incorrect method signatures in this case(some internal limitations).

Examples

File to image

Convert a File(browser object) to an Image

import converter from "javascript-binary-converter";

document
  .querySelector("#some-file-input")
  .addEventListener("change", async (event) => {
    const target = event.target;
    const files = target.files; //An array of File objects

    //Image/HtmlImageElement object
    const image = await converter(files[0]).toImage({ maxSize: 200 }); //maxSize will scale down the image, while maintaining its proportions.
    //Omit if the original size is preferred.

    document.querySelector("#image-preview").appendChild(image);
  });

 

File to bytes

If you want to get raw binary data of a File:

document
  .querySelector("#some-file-input")
  .addEventListener("change", async (event) => {
    const target = event.target;
    const files = target.files; //An array of File objects

    const bytes = await converter(files[0]).toBytes(); //Will return an array of strings, each containing 8 "bits", like:
    //[00101101,10111111,00000001...]
  });

 

Blob to Image

  import converter from 'javascript-binary-converter';

  (async () => {
  //Wrapping the code with an async function, just for the sake of example.

   const blob = new Blob([...])//Some blob you have.

   const image = await converter(blob).toImage({type:"image/png"})//You can optionally assert the type.


})();

 

Image to Uint8Array

const image = document.querySelector("#some-image");

const uint8 = await converter(image).toUnit8Array();

 

Image to bytes

If you want to get raw binary data of an Image:

const image = document.querySelector("#some-image");

const bytes = await converter(image).toBytes(); //Will return an array of strings, each containing 8 "bits", like:
//[00101101,10111111,00000001...]

 

Uint8Array to Image

Suppose you have an array of decimals, each representing a byte, in an unsigned 8 bit integer. You can convert those bytes into an html image(assuming the bytes represent an actual image):

const dummyImageBytes = [
  //These decimals(bytes) represent a tiny image
  137, 80, 78, 71, 13, 10, 26, 10, 0, 0, 0, 13, 73, 72, 68, 82, 0, 0, 0, 5, 0, 0,
  0, 6, 8, 6, 0, 0, 0, 11, 251, 84, 75, 0, 0, 0, 1, 115, 82, 71, 66, 0, 174, 206,
  28, 233, 0, 0, 0, 137, 73, 68, 65, 84, 24, 87, 1, 126, 0, 129, 255, 1, 255, 106,
  48, 255, 213, 212, 208, 0, 0, 254, 0, 0, 43, 47, 29, 0, 0, 14, 18, 0, 1, 255, 113,
  56, 255, 219, 204, 200, 0, 37, 43, 31, 0, 249, 245, 242, 0, 1, 8, 13, 0, 1, 251,
  79, 26, 255, 217, 218, 230, 0, 43, 68, 39, 0, 220, 198, 217, 0, 36, 40, 26, 0,
  1, 255, 85, 39, 255, 198, 199, 217, 0, 48, 52, 16, 0, 240, 241, 240, 0, 250, 247,
  1, 0, 1, 249, 94, 58, 255, 183, 187, 198, 0, 37, 45, 16, 0, 37, 36, 36, 0, 217,
  208, 221, 0, 1, 224, 77, 47, 255, 11, 16, 9, 0, 20, 66, 54, 0, 0, 235, 236, 0,
  226, 197, 211, 0, 66, 133, 49, 43, 23, 66, 67, 118, 0, 0, 0, 0, 73, 69, 78, 68,
  174, 66, 96, 130,
];

const uint8 = new Uint8Array(dummyImageBytes);

const image = await converter(uint8).toImage();

document.body.appendChild(image); //You can see the image in the DOM