Work out SVG viewBox attribute values

svg_viewbox_from_use.js

/*
 * 1. Load your SVGs into a page using a <use> element.
 * 2. Paste this into you developer console and run it.
 * 3. It will print out the viewBox values you need for each SVG.
 */
(() => {
  'use strict';

  let f = (e) => {
    let id = e.attributes['xlink:href'].value;
    let b = e.getBBox();
    console.log(`id: ${id} viewBox="${b.x} ${b.y} ${b.width} ${b.height}"`);
  }

  let uses = Array.from(document.querySelectorAll('use'));
  uses.forEach(f);
})();