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https://github.com/colxi/midi-parser-js

JSON Human readable MIDI sequences. Read from ArrayBuffers, Base64 encoded strings, or FileInput Element in Browsers.
https://github.com/colxi/midi-parser-js

javascript midi midi-javascript midi-js midi-parser midi-parser-js

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JSON Human readable MIDI sequences. Read from ArrayBuffers, Base64 encoded strings, or FileInput Element in Browsers.

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README 

        
![logo](https://colxi.info/midi-parser-js/docs/logo.png)



# MidiParser.js 

[![NoDependencies](https://img.shields.io/badge/dependencies-none-green.svg)](https://github.com/colxi/midi-parser-js)

[![Browser](https://img.shields.io/badge/browser-compatible-blue.svg)](https://github.com/colxi/midi-parser-js)

[![Node](https://img.shields.io/badge/node-compatible-brightgreen.svg)](https://www.npmjs.com/package/midi-parser-js)



MidiParser is a Javascript **Binary MIDI file** reader for the browser and Node which converts a MIDI binary data structure to **a JSON object**, making it much easier to iterate over and interact with.



- Tiny and dependency free

- Browser & Node Compatible

- Supported data input : 

  -  ```BASE64``` encoded Midi data

  - ```UINT8``` arrayBuffer, obtained when reading or fetching a   .mid binary. 

  - ```FileInput Element``` in the Browser 

- Custom Midi Messages



## Example



A simple example parsing a MIDI file in Node ...

```javascript

let midiParser  = require('midi-parser-js');

let fs = require('fs')



// read a .mid binary (as base64)

fs.readFile('./test.mid', 'base64', function (err,data) {

  // Parse the obtainer base64 string ...

  var midiArray = midiParser.parse(data);

  // done!

  console.log(midiArray);

});

```



Example in Browser...

```html



  import MidiParser from 'midi-parser-js'

  // select the INPUT element that will handle

  // the file selection.

  let source = document.getElementById('filereader');

  // provide the File source and a callback function

  MidiParser.parse( source, function(obj){

    console.log(obj);

  });



```

If you want to see it in action, you can test it [Here](https://colxi.info/midi-parser-js/test/test-es6-import.html)



## Syntax:



```javascript

  MidiParser.parse( input [, callback] );

```

**- input** : Accepts any of the supported Data Sources : `FileInputElement  | uint8Array | base64String`



**- callback** : Callback to be executed when data is parsed. Only required when input is a `FileInputElement`. 

 



---



## Handle Custom messages ( sysEx, non-standard...)



By default, the library ignores the sysEx, and non-standard messages, simply converting their values to integers (when possible).

However you can provide a custom hook function to be executed when any non-standard message is found, and process it by your own, returning the resulting value.



```javascript 

MidiParser.customInterpreter = function( msgType, arrayBuffer, metaEventLength){  /* your code */ }

```



**- msgType** : Hex value of the message type

 

**- arrayBuffer** : Dataview of the midi data. You have to extract your value/s from it, moving the pointer as needed.



**- metaEventLength** : A length greater than 0 indicates a received message



> If you want the default action to be executed, return **false**



## Output JSON anatomy  :



The returned JSON object contains all the attributes of the MIDI file (format type, time division, track count... ) as properties. The tracks and the MIDI events related to each track are container inside the `track` property. 



![logo](https://colxi.info/midi-parser-js/docs/diagram.jpg)



The following JSON object represents a MIDI file with **3 tracks** and **4 events** in **Track 0**



```javascript

outputObject{

....formatType: 0|1|2,  // Midi format type

....timeDivision: (int),  // song tempo (bpm)

....tracks: (int),  // total tracks count

....track: Array[

........[0]: Object{  // TRACK 1!

............event: Array[  // Midi events in track 1

................[0] : Object{  // EVENT 1

....................data: (string),

....................deltaTime: (int),

....................metaType: (int),

....................type: (int)

................},

................[1] : Object{...},  // EVENT 2

................[2] : Object{...}, // EVENT 3

................[3] : Object{...}  // EVENT 4

............]

........},

........[1] : Object{...},  // TRACK 2

........[2] : Object{...}  // TRACK 3

....]

}

```

If you want to read the data from **Event 2** of **Track 0** , you should use the following keypath :



```javascript

outputObject.track[0].event[2].data;

```

---

 

## Distribution & Installation :



The following distribution channels are available :



**- NPM** : Install using the following command :



```bash

  $ npm install midi-parser-js -s

```



**- GIT** : You can clone the repository  :

```bash

  $ git clone https://github.com/colxi/midi-parser-js.git

```



**-ZIP** : Or download the package in a ZIP file from

> [GITHUB LATEST PACKAGE RELEASE PAGE](https://github.com/colxi/midi-parser-js/releases/latest)



**-CDN** : Include the latest release of this library in your HTML head using the CDN :

> Warning : Not recommended for production enviroments!



```html



```

## Importing

This package is shipped with support to Node CommonJS and ES6 Modules. Use the appropiate method accoordintg to your enviroment.



```javascript

  // ES6 Module Import : 

  import {MidiParser} from './midi-parser.js'; 



  // CommonJS Node Import :

  let MidiParser = require('midi-parser-js');

```



--- 

## Bonus : MIDI File Format Specifications :



MIDI Binary Encoding Specifications in https://github.com/colxi/midi-parser-js/wiki/MIDI-File-Format-Specifications