Pretty fast base85 JavaScript library (with TS support).
It is designed to encode binary data (Uint8Array) into a “base85” text string and vice versa.
npm install @alttiri/base85
function encode(ui8a: Uint8Array, charset?: "ascii85" | "z85" | string): stringencode encodes the input Uint8Array into base85 string.
function decode(base85: string, charset?: "ascii85" | "z85" | string): Uint8Arraydecode decodes the input base85 string into Uint8Array.
charset is “z85” by default.
Also, there are encodeBase85 and decodeBase85 aliases for encode and decode functions.
Binary data encoding example:
import {encodeBase85} from "@alttiri/base85";
// png image, 169 bytes
const imageBytes = new Uint8Array([137,80,78,71,13,10,26,10,0,0,0,13,73,72,68,82,0,0,0,32,0,0,0,32,8,2,0,0,0,252,24,237,163,0,0,0,1,115,82,71,66,0,174,206,28,233,0,0,0,4,103,65,77,65,0,0,177,143,11,252,97,5,0,0,0,9,112,72,89,115,0,0,14,195,0,0,14,195,1,199,111,168,100,0,0,0,62,73,68,65,84,72,75,237,210,49,10,0,48,8,197,80,239,127,105,187,252,161,208,150,32,93,243,86,149,44,86,191,213,33,131,9,3,200,0,50,128,12,160,92,74,63,242,77,55,217,216,100,48,97,0,25,64,6,144,1,208,189,0,183,189,228,126,66,93,37,1,0,0,0,0,73,69,78,68,174,66,96,130]);
const base85 = encodeBase85(imageBytes);
console.log(base85);
console.log(base85.length);
// "Ibl@q4gj0X0000dnK#lE0000w0000w2M:#a0q)Y3Qw$n]0DRdeliagl9o^C600D}2o*F:VV5Yp<vfDSh010Qns-TMy4-nnD4-ns/z(vgD002hOl{T^yoypdZ3ih:=-zD2Mx$Kqp^3t!W]h.bcr>)fdG9.U305x6kPJ>8N[>z6@/KMWA02X3aKo9.w0jPV5ENmr^0rr9107/QOm6n<:F="
// 212
If you need to encode a text (are you really need it?) use TextEncoder/TextDecoder.
const input = "Man is distinguished";
const inputBytes = utf8StringToArrayBuffer(input);
console.log(encode(inputBytes, "ascii85")); // "9jqo^BlbD-BleB1DJ+*+F(f,q"
console.log(encode(inputBytes, "z85")); // "o<}]Zx(+zcx(!xgzFa9aB7/b}"
const outputBytes = decode("9jqo^BlbD-BleB1DJ+*+F(f,q", "ascii85");
const output = arrayBufferToUtf8String(outputBytes);
console.log(output); // "Man is distinguished"
For more examples see the tests.
You can test the lib online in the browser’s console: https://alttiri.github.io/base85/online
All required things are already in the global scope. (encode, decode; util functions: utf8StringToArrayBuffer and others.)
Note.
The optimisation for "ascii85" by replacing "\0\0\0\0" by "z" instead of "!!!!!" and " " (4 spaces) by "y" instead of "+<VdL" is not supported.
Anyway nobody forbids you to do something like base85.replaceAll("!!!!!", "z") as well as to add "<~", "~>" manually if you need it.
/** 85 unique characters string */
type CharSet = string;
/**
* Returns Base85 string.
* @param {Uint8Array} ui8a - input data to encode
* @param {"ascii85" | "z85" | string} [charset="z85"] - 85 unique characters string
* @return {string}
* */
export declare function encode(ui8a: Uint8Array, charset?: "ascii85" | "z85" | CharSet): string;
/**
* Decodes Base85 string.
* @param {string} base85 - base85 encoded string
* @param {"ascii85" | "z85" | string} [charset="z85"] - 85 unique characters string
* @return {Uint8Array}
* */
export declare function decode(base85: string, charset?: "ascii85" | "z85" | CharSet): Uint8Array;
/** Alias to `encode`. */
export declare const encodeBase85: typeof encode;
/** Alias to `decode`. */
export declare const decodeBase85: typeof decode;
declare const base85: {
encode: typeof encode;
decode: typeof decode;
encodeBase85: typeof encode;
decodeBase85: typeof decode;
};
export default base85;
npm install @alttiri/base85
npm install git+https://github.com/alttiri/base85.git