Triangulates obj text, depends on three.js and earcut, supports convex and concave polygon without holes.
Make sure your obj file contains normal coords, the first vertex's normal in a face will be used for rotation (rotate the face to parallel to the XY plane), because earcut handles 3D data as if it was projected onto the XY plane.
npm install --save three-obj-earcut
import triangulate from 'three-obj-earcut'
const result = triangulate(objText)