JSFiddle - React, Tailwind, and code Playground

HTML

<svg>
    <g id="g">
        <path id="p" d="M40 20h0" fill="none" stroke="red" />
        <rect id="r" x="50" y="50" width="50" height="50" fill="green" />
    </g>
</svg>

JavaScript

var b = document.getElementById("p").getBBox();
document.body.innerHTML += "<br/>path bbox: [" + b.x + ", " + b.y + ", " + b.width + ", " + b.height + "]";
b = document.getElementById("r").getBBox();
document.body.innerHTML += "<br/>rect bbox: [" + b.x + ", " + b.y + ", " + b.width + ", " + b.height + "]";
b = document.getElementById("g").getBBox();
document.body.innerHTML += "<br/>g bbox: [" + b.x + ", " + b.y + ", " + b.width + ", " + b.height + "]";