數據訪問和同步標準JS庫：Orbit.js

Orbit.js 是一個標準庫用于協調訪問數據源，并保持它們的內容同步。Orbit提供了一個基礎框架，用于在客戶端應用程序構建高級功能比較：離線操作，維護和同步本地高速緩存，撤消/重做棧和特設的編輯環境。

目標：

• Support any number of different data sources in an application and provide access to them through common interfaces.

• Allow for the fulfillment of requests by different sources, including the ability to specify priority and fallback plans.

• Allow records to simultaneously exist in different states across sources.

• Coordinate transformations across sources. Handle merges automatically where possible but allow for complete custom control.

• Allow for blocking and non-blocking transformations.

• Allow for synchronous and asynchronous requests.

• Support transactions and undo/redo by tracking inverses of operations.

• Work with plain JavaScript objects.

 // Create data sources with a common schema
  var schema = {
    idField: '__id',
    models: {
      planet: {
      }
    }
  };
  var memorySource = new Orbit.MemorySource(schema);
  var restSource = new Orbit.JSONAPISource(schema);
  var localSource = new Orbit.LocalStorageSource(schema);

  // Connect MemorySource -> LocalStorageSource (using the default blocking strategy)
  var memToLocalConnector = new Orbit.TransformConnector(memorySource, localSource);

  // Connect MemorySource <-> JSONAPISource (using the default blocking strategy)
  var memToRestConnector = new Orbit.TransformConnector(memorySource, restSource);
  var restToMemConnector = new Orbit.TransformConnector(restSource, memorySource);

  // Add a record to the memory source
  memorySource.add('planet', {name: 'Jupiter', classification: 'gas giant'}).then(
    function(planet) {
      console.log('Planet added - ', planet.name, '(id:', planet.id, ')');
    }
  );

  // Log the transforms in all sources
  memorySource.on('didTransform', function(operation, inverse) {
    console.log('memorySource', operation);
  });

  localSource.on('didTransform', function(operation, inverse) {
    console.log('localSource', operation);
  });

  restSource.on('didTransform', function(operation, inverse) {
    console.log('restSource', operation);
  });

  // CONSOLE OUTPUT
  //
  // memorySource {op: 'add', path: 'planet/1', value: {__id: 1, name: 'Jupiter', classification: 'gas giant'}}
  // localSource  {op: 'add', path: 'planet/1', value: {__id: 1, name: 'Jupiter', classification: 'gas giant'}}
  // restSource   {op: 'add', path: 'planet/1', value: {__id: 1, id: 12345, name: 'Jupiter', classification: 'gas giant'}}
  // memorySource {op: 'add', path: 'planet/1/id', value: 12345}
  // localSource  {op: 'add', path: 'planet/1/id', value: 12345}
  // Planet added - Jupiter (id: 12345)

項目主頁：http://www.baiduhome.net/lib/view/home/1390181638586