Calling a method inside another

Question

I'm getting this error message when i run this code : index.js:19 Uncaught TypeError: this.getRandomColor is not a function at setUp (index.js:19)

I used this. to refer to the getRandomColor method but it doesn't work. Can't figure out why.

class Renderer {
constructor() {
    this.setUpAfterDelay();
}
setUp() {

    let width = Math.random() * 300;
    let height = Math.random() * 300;
    let top = Math.random() * 200;
    let left = Math.random() * 200;


    let shape = document.createElement("div");
    shape.style.width = width + "px";
    shape.style.height = height + "px";
    shape.style.position = "absolute";
    shape.style.top = top + "px";
    shape.style.left = left + "px";
    shape.style.backgroundColor = this.getRandomColor();
    document.body.appendChild(shape);

}
setUpAfterDelay() {
    setTimeout(this.setUp, Math.random() * 2000);

}

getRandomColor() {
    var letters = '0123456789ABCDEF';
    var color = '#';
    for (var i = 0; i < 6; i++) {
        color += letters[Math.floor(Math.random() * 16)];
    }
    return color;
}
}

let renderer = new Renderer;