enbock / Time-Tracker

export default class ModuleLoader {

  moduleState: IObserver<typeof React.Component | null>;

  moduleNameState: IObserver<string>;

  dictionary: ILoadedModuleDictionary;

  pathToRoot: string;

  constructor(

    pathToRoot: string,

    moduleNameState: IObserver<string>,

    moduleState: IObserver<typeof React.Component | null>

  ) {

    this.moduleNameState = moduleNameState;

    this.moduleState = moduleState;

    this.dictionary = {};

    this.pathToRoot = pathToRoot;

    this.moduleNameState.adapter.onChange = this.loadModule.bind(this);

  }

  async loadModule(oldValue: string, newValue: string) {

    let module: typeof React.Component;

    if (!this.dictionary.hasOwnProperty(newValue)) {

      module =

        (

          await import(this.pathToRoot + newValue + '.js')

        ).default as typeof React.Component;

      this.dictionary[newValue] = module;

    } else {

      module = this.dictionary[newValue];

    }

    this.moduleState.value = module;

  }

}