east Function – forMeshTriangles

const forMeshTriangles: (
  mesh: GeometryArray,
  callback: (
    v1: vec3,
    v2: vec3,
    v3: vec3,
    index: number,
    i1: number,
    i2: number,
    i3: number,
  ) => void,
) => void

Source

packages / workbench / src / primitives / geometry / util.ts