threejs v87: traverse materials and map function

traverseMaterials.js

import _ from 'lodash';

export default function traverseMaterials(object, callback) {
  // multi material
  if (_.isArray(object.material)) {
    _.forEach(object.material, (material) => {
      callback(material);
    });
    return;
  }

  // multi material of old threejs version
  if (object.material.materials) {
    _.forEach(object.material.materials, (material) => {
      callback(material);
    });
    return;
  }

  callback(object.material);
}