A < 20 line (Hack-ish) A-Frame Outline Geometry component

outline-geometry-component.js

AFRAME.registerComponent('outline-geometry', {
    schema : {
        margin : { default : 1.025 },
        color: { default : 'red' },
    },
    init : function () {
        var p = this.el;
        var p_prime = p.cloneNode(true);
        p_prime.removeAttribute('outline-geometry')
        p_prime.setAttribute('material', 'color', this.data.color)
        p_prime.setAttribute('material', 'side', 'back')
        p_prime.setAttribute('position', '0 0 0')
        let s = this.data.margin
        p_prime.setAttribute('scale', `${s} ${s} ${s}`)
        this.el.appendChild(p_prime)
    }
})

Here it is ✨in real life✨