openproject/frontend/app/components/common/lazy/lazy.service.ts

// -- copyright
// OpenProject is a project management system.
// Copyright (C) 2012-2015 the OpenProject Foundation (OPF)
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License version 3.
//
// OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
// Copyright (C) 2006-2013 Jean-Philippe Lang
// Copyright (C) 2010-2013 the ChiliProject Team
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
//
// See doc/COPYRIGHT.rdoc for more details.
// ++

function lazy (obj:any, property:string, getter:{():any}, setter?:{(value:any)}) {
  if (angular.isObject(obj)) {
    let done = false;
    let value;
    let config = {
      get() {
        if (!done) {
          value = getter();
          done = true;
        }
        return value;
      },
      set: void 0,

      configurable: true,
      enumerable: true
    };

    if (setter) {
      config.set = val => {
        value = setter(val);
        done = true;
      };
    }

    Object.defineProperty(obj, property, config);
  }
}

angular
  .module('openproject.services')
  .factory('lazy', () => lazy);