node_modules/three/src/loaders/MaterialLoader.d.ts

import { LoadingManager } from './LoadingManager';
import { Texture } from './../textures/Texture';
import { Material } from './../materials/Material';

export class MaterialLoader {
  constructor(manager?: LoadingManager);

  manager: LoadingManager;
  textures: { [key: string]: Texture };

  load(
    url: string,
    onLoad: (material: Material) => void,
    onProgress?: (event: ProgressEvent) => void,
    onError?: (event: Error | ErrorEvent) => void
  ): void;
  setTextures(textures: { [key: string]: Texture }): void;
  getTexture(name: string): Texture;
  parse(json: any): Material;
}