Question

假设我有一个状态

的骨干模型

var myModel = new Backbone.Model(
    {
        key1:'value1', 
        key2:'value2', 
        key3:'value3'
    });

myModel.on('all', function allHanlder () {
    console.log(arguments);
})

我需要删除key1和key2并更改key3。可能的选项是

取消设置key1和key2，设置key3属性
清除模型并设置key3

选项1导致3次更改，3次更改属性事件

myModel.unset('key1');
myModel.unset('key2');
myModel.set({key3:'newValue3'})

//events


["change:key1", Object { cid="c1355", attributes={...}, _changing=true, more...}, undefined, Object { unset=true}]
["change", Object { cid="c1355", attributes={...}, _changing=true, more...}, Object { unset=true}]
["change:key2", Object { cid="c1355", attributes={...}, _changing=true, more...}, undefined, Object { unset=true}]
["change", Object { cid="c1355", attributes={...}, _changing=true, more...}, Object { unset=true}]
["change:key3", Object { cid="c1355", attributes={...}, _changing=true, more...}, "newValue3", Object {}]
["change", Object { cid="c1355", attributes={...}, _changing=true, more...}, Object {}]

选项2将导致2个更改更改：属性事件

myModel.clear()
myModel.set({key3:'newValue3'})

//output


["change:key1", Object { cid="c1356", attributes={...}, _changing=true, more...}, undefined, Object { unset=true}]
["change:key2", Object { cid="c1356", attributes={...}, _changing=true, more...}, undefined, Object { unset=true}]
["change:key3", Object { cid="c1356", attributes={...}, _changing=true, more...}, undefined, Object { unset=true}]
["change", Object { cid="c1356", attributes={...}, _changing=true, more...}, Object { unset=true}]
["change:key3", Object { cid="c1356", attributes={...}, _changing=true, more...}, "newValue3", Object {}]
["change", Object { cid="c1356", attributes={...}, _changing=true, more...}, Object {}]

更改：属性事件是公平的，但我需要最小化更改触发器。像下面的东西。

myModel.someMagicSet({key3:'newValue3'})

//output

["change:key1", Object { cid="c1355", attributes={...}, _changing=true, more...}, undefined, Object {}]
["change:key2", Object { cid="c1355", attributes={...}, _changing=true, more...}, undefined, Object {}]
["change:key3", Object { cid="c1355", attributes={...}, _changing=true, more...}, "newValue3", Object {}]
["change", Object { cid="c1355", attributes={...}, _changing=true, more...}, Object {}]

我是否有办法在不超越骨干行为的情况下实现它？

Answer 1

myModel.unset('key1', {silent: true});
myModel.unset('key2', {silent: true});
myModel.set({key3:'newValue3'}, {removed: ['key1', 'key2']});

只需触发一个更改事件，这将执行您想要的操作。您将已删除的项目传递给options对象中的处理程序。在您的处理程序中，您的代码应如下所示：

myModel.on('all', function allHandler (model, options) {
    console.log(options.removed);  // this should show you what has been removed before
    // other code
})

或者，您可以在选项中传递一个标记，您可以在处理程序中分析每个事件，这将确定处理程序是否已运行。这将使您的处理程序可以访问已更改的内容，但是它必须将其存储在其自己的范围之外，以便下次访问它。

myModel.unset('key1', {finished: false});
myModel.unset('key2', {finished: false});
myModel.set({key3:'newValue3'}, {finished: true});

编辑：这是一个应该做的所有事情：

myModel.clear({reset: {key3: 'newValue3'}});

然后在你的处理程序中执行此操作

myModel.on('all', function allHandler (model, options) {
  if (options.reset){        
    model.set(options.reset);
  }
    // other code
})

你应该注意的是clear也删除了id，所以如果你需要，你应该将它传递给你：

myModel.clear({reset: {key3: 'newValue3', id: myModel.get('id')}});

骨干模型在同一方法调用中设置和取消设置

1 个答案: