const quaternionFromNormal = require('three-quaternion-from-normal');

// Say we want mesh to point from A to B point
const A = new THREE.Vector3(1, 0, 0);
const B = new THREE.Vector3(2, 5, -1);

// Get normal A->B
const normal = B.clone().sub(A).normalize();

// Get orientation
const quaternion = quaternionFromNormal(normal);

// Apply orientation to mesh
mesh.quaternion.copy(quaternion);