innomatrix · December 6, 2020 22:09
diff --git a/area-polyfill.js b/area-polyfill.js
 Math.area = Math.area || function(polygon){
  const length = polygon.length;

  let sum = 0;

  for(let i = 0; i < length; i += 2){
    sum += polygon[i    ] * polygon[(i + 3) % length]
         - polygon[i + 1] * polygon[(i + 2) % length];
  }

  return Math.abs(sum) * 0.5;
 }
diff --git a/usage.js b/usage.js
 Math.area([
  0, 0,
  3, 0,
  0, 4
 ]); // 6
	Math.area = Math.area \|\| function(polygon){
	const length = polygon.length;

	let sum = 0;

	for(let i = 0; i < length; i += 2){
	sum += polygon[i ] * polygon[(i + 3) % length]
	- polygon[i + 1] * polygon[(i + 2) % length];
	}

	return Math.abs(sum) * 0.5;
	}