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https://github.com/alttiri/base85

Pretty fast base85 JavaScript library
https://github.com/alttiri/base85

ascii85 base64 base85 z85

Last synced: about 2 months ago
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Pretty fast base85 JavaScript library

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README 

        
# base85

[Pretty fast](https://github.com/AlttiRi/base85/blob/7a6edf4b9c0b16e0d63e35c0c102c1875f78ddb0/tests/test-2-speed.js#L23-L52) base85 JavaScript library (with TS support).



It is designed to encode binary data (`Uint8Array`) into a "base85" text string and vice versa.



```bash

npm install @alttiri/base85

```



## API



#### `function encode(ui8a: Uint8Array, charset?: "ascii85" | "z85" | string): string`



[`encode`](https://github.com/AlttiRi/base85/blob/45b6cf40a85c475855f739cecd98845b4ede2b1e/base85.ts#L48) encodes the input `Uint8Array` into base85 `string`.



#### `function decode(base85: string, charset?: "ascii85" | "z85" | string): Uint8Array`



[`decode`](https://github.com/AlttiRi/base85/blob/45b6cf40a85c475855f739cecd98845b4ede2b1e/base85.ts#L90) decodes the input base85 `string` into `Uint8Array`.



`charset` is "z85" by default.



Also, there are `encodeBase85` and `decodeBase85` aliases for `encode` and `decode` functions.



## Examples



Binary data encoding example:

```js

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)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`](https://github.com/AlttiRi/base85/blob/45b6cf40a85c475855f739cecd98845b4ede2b1e/tests/util.js#L17-L29).



```js

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](https://github.com/AlttiRi/base85/tree/master/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 `"+"` manually if you need it.



---



# *.d.ts



```ts

/** 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;

```



---



## Installation



### From NPM



```bash

npm install @alttiri/base85

```



### From GitHub repository



```bash

npm install git+https://github.com/alttiri/base85.git

```



More ways



### From GitHub repository (a specific version):



- **Based on SemVer:**

    ```bash

    npm install git+https://github.com/alttiri/base85.git#semver:1.5.1

    ```

  Or add

    ```

    "@alttiri/base85": "github:alttiri/base85#semver:1.5.1"

    ```

  as `dependencies` in `package.json` file.



  See available [tags](https://github.com/AlttiRi/base85/tags).



- **Based on a commit hash:**

    ```bash

    npm install git+https://[email protected]/alttiri/base85.git#ca3217f3d1075b8ff0966e24437326a6c2537bbc

    ```

  Or add

    ```

    "@alttiri/base85": "github:alttiri/base85#ca3217f3d1075b8ff0966e24437326a6c2537bbc"

    ```

  as `dependencies` in `package.json` file.



  See available [commits hashes](https://github.com/AlttiRi/base85/commits/master).



### From GitHub Packages:

To install you need first to create `.npmrc` file with `@alttiri:registry=https://npm.pkg.github.com` content:

```bash

echo @alttiri:registry=https://npm.pkg.github.com >> .npmrc

```



only then run



```bash

npm install @alttiri/base85

```

Note, that GitHub Packages requires to have also `~/.npmrc` file (`.npmrc` in your home dir) with `//npm.pkg.github.com/:_authToken=TOKEN` content, where `TOKEN` is a token with the `read:packages` permission, take it here https://github.com/settings/tokens/new.