Method Composition in JavaScript

MethodComposition.js

function composeMethods(...methods){
    //use a normal function, not an arrow, as we need "dynamic this"
    return function(...args) {
        methods.forEach(method => {
            let methodArgs = args.splice(0, method.length);
            method.call(this, ...methodArgs);
        })
    }
}


class Particle{
    constructor(x, y, opacity){
        this.x = x || 0;
        this.y = y || 0;
        this.opacity = 1;
    }

    move(x, y){
        this.x += x;
        this.y += y;
    }

    fade(v){
        this.opacity += v;
    }
}

//composing "move" and "fade" and adding it as a new "moveAndFade" method
Particle.prototype.moveAndFade = composeMethods(Particle.prototype.move, Particle.prototype.fade);

let p1 = new Particle();
console.log(JSON.stringify(p1));

//x, y, v
p1.moveAndFade(4, 8, -0.1);
console.log(JSON.stringify(p1));

p1.moveAndFade(2, 3, -0.2);
console.log(JSON.stringify(p1));

// {"x":0,"y":0,"opacity":1}
// {"x":4,"y":8,"opacity":0.9}
// {"x":6,"y":11,"opacity":0.7}