p5.js Keyboard key

The key variable in p5.js always contains the value of the key which is recently pressed. To get the proper capitalisation, it is best to use it within keyTyped(). Use the keyCode variable For non-ASCII keys.

Syntax:

key

Below program illustrates the key variable in p5.js:
Example-1:

let valueX;
let valueY;

function setup() {

    // Create Canvas of size 500*500
    createCanvas(1000, 500);
}

function draw() {

    // set background color
    background(200);

    fill('green');
    // set text and text size
    textSize(25);
    text(
      'Press Any Key to change the text within circle'
      , 30, 30);

    // use of keyIsPressed Variable
    if (keyIsPressed) {
        // draw ellipse
        ellipse(mouseX, mouseY, 115, 115);
        fill('red');
        text("Key Is Pressed", 100, 300);
        textSize(100);
        text(key, mouseX, mouseY);
    }

    else {
        rect(mouseX / 2, mouseY / 2, 300, 200);
        text(key, mouseX, mouseY);
    }

}

Output:

Example-2:

let valueX;
let valueY;

function setup() {

    // Create Canvas of size 500*500
    createCanvas(500, 500);
}

function draw() {

    // set background color
    background(200);

    fill('green');

    // set text and text size
    textSize(100);

    text(key, height / 2, width / 2);
    if (keyIsPressed) {
        textSize(40);
        text("is pressed", height / 7, width - 50);
    }

}

Output:

Reference: https://p5js.org/reference/#/p5/key