使用坐标，获取扇形（Sector）的Path data（起始点、结束点、半径、开启角度、结束角度）

pathSector.js

function describeArc(x, y, radius, startAngle, endAngle) {
  var start = polarToCartesian(x, y, radius, endAngle);
  var end = polarToCartesian(x, y, radius, startAngle);

  console.log('start: ', start);
  console.log('end: ', end);

  var largeArcFlag = Math.abs(endAngle - startAngle) <= 180 ? "0" : "1";
  const clockwise = endAngle < 0 ? 1 : 0;

  var d = [
      "M", start.x, start.y, 
      "A", radius, radius, 0, largeArcFlag, clockwise, end.x, end.y,
      "L", x, y,
      "Z"
  ].join(" ");

  return d;
}

function degree2Radian(degrees) {
  // return degrees * Math.PI / 180;
  return (degrees - 90) * Math.PI / 180;
}

function radian2Degree(radians) {
  return radians * 180 / Math.PI;
}

function polarToCartesian(centerX, centerY, radius, angleInDegrees) {
  const angleInRadians = degree2Radian(angleInDegrees);

  return {
    x: centerX + (radius * Math.cos(angleInRadians)),
    y: centerY + (radius * Math.sin(angleInRadians))
  };
}