For a game engine I am making with three js I need to put it into a class. But now when I put it into the class everything works except when I tell the requestAnimateFrame() to link to itself it says "BEngine.js:19 Uncaught TypeError: Cannot read properties of undefined (reading 'animate')".

export class BEngine
{
    constructor(doc){
        this.scene = new THREE.Scene();
        this.camera = new THREE.PerspectiveCamera(
            75,
            window.innerWidth / window.innerHeight,
            0.1,
            1000
        );
        this.renderer = new THREE.WebGLRenderer({ antialias: true });
        this.renderer.setSize(window.innerWidth, window.innerHeight);
        doc.body.appendChild(this.renderer.domElement);
        window.addEventListener("resize", this.onWindowResize, false);
    }
    animate() 
    {
        requestAnimationFrame(this.animate);
        this.renderer.render(this.scene, this.camera);
    }
    onWindowResize() {
        camera.aspect = window.innerWidth / window.innerHeight;
        camera.updateProjectionMatrix();
        renderer.setSize(window.innerWidth, window.innerHeight);
    }
}