<!DOCTYPE html>
<meta charset="utf-8">
<body>
<svg style="border: 1px solid gray;">
  <text id="test-text" y="0" x="50" font-size="16" writing-mode="vertical-rl">🎓👺👕👖👢</text>
</svg>
<p id="result"></p>

<script>
var text  = document.getElementById("test-text");
var bbox = text.getBBox();
result.textContent = `BBox: ${bbox.width} x ${bbox.height}`;
</script>
</body>
