percent-to-path.js

const percent = 0.12;

const startX = getCoordinatesForPercent(0)[0];
const startY = getCoordinatesForPercent(0)[1];
const endX = getCoordinatesForPercent(percent)[0];
const endY = getCoordinatesForPercent(percent)[1];

const largeArcFlag = percent > .5 ? 1 : 0;

const pathData = [
  `M ${startX} ${startY}`,
  `A 1 1 0 ${largeArcFlag} 1 ${endX} ${endY}`,
  `L 0 0`,
].join(' ');