Creating a Piano using Reactjs - Audio( ) WebAPI and Hooks

Atharva Pingale — Tue, 12 Jul 2022 12:59:44 +0000

I recently participated in the Hackbytes hackathon 2022 on Devfolio, where I had created a piano using Reactjs. It was too good to be real. So, I thought of sharing the processs of actually creating one using Reactjs. Note that I will be ignoring the CSS Part and will only be focussing on Javascript.

So get Ready !

Download all the key sounds in mp3 format

The first thing it to download all the key sounds. You must have a minimum of 7 white key sounds + 5 black key sounds = 12 key sounds ( 1 octave ) of any scale.

I recommend downloading all the mp3 files from here - https://freesound.org/people/Tesabob2001/packs/12995/
OR you can download the zip file of my repo on Github and navigate to - /client/src/Components/Music/Sounds and extract all of them.

Store all the mp3 files in a folder named 'Sounds'
Rename all the files in the below format for simplicity.

Javascript Code

Now comes the fun part! Which is the code. Create a component first ( a js/jsx file ). We will then have to create an object of the class ' Audio ' and access its properties to play the sound.
Sample code :

We will be creating an object for each and every mp3 file.

  const C4 = new Audio(require('./Sounds/C4.mp3'));
  const Db4 = new Audio(require("./Sounds/Db4.mp3"));
  const D4 = new Audio(require("./Sounds/D4.mp3"));
  const Eb4 = new Audio(require("./Sounds/Eb4.mp3"));
  const E4 = new Audio(require("./Sounds/E4.mp3"));
  const F4 = new Audio(require("./Sounds/F4.mp3"));
  const Gb4 = new Audio(require("./Sounds/Gb4.mp3"));
  const G4 = new Audio(require("./Sounds/G4.mp3"));
  const Ab4 = new Audio(require("./Sounds/Ab4.mp3"));
  const A4 = new Audio(require("./Sounds/A4.mp3"));
  const Bb4 = new Audio(require("./Sounds/Bb4.mp3"));
  const B4 = new Audio(require("./Sounds/B4.mp3"));
  const C5 = new Audio(require("./Sounds/C5.mp3"));
  const Db5 = new Audio(require("./Sounds/Db5.mp3"));
  const D5 = new Audio(require("./Sounds/D5.mp3"));
  const Eb5 = new Audio(require("./Sounds/Eb5.mp3"));
  const E5 = new Audio(require("./Sounds/E5.mp3"));

The next step is to create a function named playSound() which will accept audio object as an argument, create a cloned node and play the audio.
More information about cloneNode() can be found on the official docs - cloneNode() MDN Docs | HTMLAudioElement MDN Docs | play() MDN Docs

  const playSound = audio => {
    // creating a cloned node of the audio object
    const clone = audio.cloneNode()

    // calling the play() method to play the mp3 file
    clone.play()
  }

Next is importing the useState hook and we will be creating a variable named the piano key and a modifier function which will have a boolean value. This will toggle the state of the variable when we click on a particular key ( meaning - that when we click on a button ). If the key is clicked, we set the toggle_Key_ to ' True ' , else ' False '.We will be creating useState hooks for each and every key.

import { useState } from 'react';

  // keys 
  const [C4Key , toggleC4key] = useState(false);
  const [Db4Key , toggleDb4key] = useState(false);
  const [D4Key , toggleD4key] = useState(false);
  const [Eb4Key , toggleEb4key] = useState(false);
  const [E4Key , toggleE4key] = useState(false);
  const [F4Key , toggleF4key] = useState(false);
  const [Gb4Key , toggleGb4key] = useState(false);
  const [G4Key , toggleG4key] = useState(false);
  const [Ab4Key , toggleAb4key] = useState(false);
  const [A4Key , toggleA4key] = useState(false);
  const [Bb4Key , toggleBb4key] = useState(false);
  const [B4Key , toggleB4key] = useState(false);
  const [C5Key , toggleC5key] = useState(false);
  const [Db5Key , toggleDb5key] = useState(false);
  const [D5Key , toggleD5key] = useState(false);
  const [Eb5Key , toggleEb5key] = useState(false);
  const [E5Key , toggleE5key] = useState(false);

Next is Creating the onClick() function. This is the function which will be called when a button is clicked. An event object will be passed to the function which will invoke 2 functions - playSound() and toggleKey() functions. We will be creating onClick() functions for each and every key ( ie- 12 keys ).

  const playC4 = (e) => {
    playSound(C4);
    toggleC4key(true);
    setTimeout(() => {
        toggleC4key(false);
    }, 200);
  }

Create similar functions named - playDb4, playD4, playEb4 .... and pass the respective audio objects to the playSound() function.
The setTimeout() function here is used as a time Period for which the particular key will be in active ( toggled as true ) state ( ie - for how long is it pressed ). I have set the value to 200ms, which after 200ms the key will be toggled off.

Next, will be creating a button element and defining the onClick() handler.

<button className='white-btn C4' onClick={(e)=> playC4(e)} />
<button className='Db4' onClick = {(e) => playDb4(e)} />
<button className='white-btn D4' onClick={(e)=> playD4(e)} />
<button className='white-btn E4' onClick={(e)=> playE4(e)} />
<button className='white-btn F4' onClick={(e)=> playF4(e)} />

Replicate the buttons for the rest of the keys as well and the piano should be done! You can check the code on my github for any help - Code | all the mp3 audio files can be extracted from Audio Files | Repo Link - Github Repo | Use the app here Heroku App. Cover Image credits : Wallpaper Access

DEV Community: Atharva Pingale

Creating a Piano using Reactjs - Audio( ) WebAPI and Hooks

Download all the key sounds in mp3 format

Javascript Code