from Computational Geometry: Algorithms and Applications book
var convexHull = require('graham-scan-convex-hull');
var coords = [
[0, 1],
[2, 0],
[3, 1],
[2, 2],
[2, 1]
]
console.log(convexHull(coords));
// prints [[0, 1],[2, 0],[3, 1],[2, 2]]