makeFindOne

  • function
 

makeFindOne is a hook that lets you define special findOne behavior. It is a generator function that lets you return the function that will actually be called when findOne is called.

can.Model.makeFindOne: function(findOneData) -> findOne

Returns the external findOne method given the implemented findOneData function.

Parameters

  1. findOneData {findOneData(params)}

    findOne is implemented with a String, ajax settings object, or findOneData function. If it is implemented as a String or ajax settings object, those values are used to create a findOneData function.

    The findOneData function is passed to makeFindOne. makeFindOne should use findOneData internally to get the raw data for the request.

Returns

{function(params, success, error)}

Returns function that implements the external API of findOne.

Use

When a user calls MyModel.findOne({}), the function returned by makeFindOne will be called. Here you can specify what you want to happen before the real request for data is made. Call the function passed in findOneData with params to make the AJAX request, or whatever the external request for data normally does.

makeFindOne can be used to implement base models that perform special behavior, like caching, or adding special parameters to the request object. makeFindOne is passed a findOneData function that retrieves raw data. It should return a function that when called, uses the findOneData function to get the raw data and convert it to a model instance with model.

Caching

The following uses makeFindOne to create a base CachedModel:

CachedModel = can.Model.extend({
 makeFindOne: function(findOneData){
   // A place to store requests
   var cachedRequests = {};

   return function(params, success, error){
     // is this not cached?
     if(! cachedRequests[JSON.stringify(params)] ) {
       var self = this;
       // make the request for data, save deferred
       cachedRequests[JSON.stringify(params)] =
         findOneData(params).then(function(data){
           // convert the raw data into instances
           return self.model(data)
         })
     }
     // get the saved request
     var def = cachedRequests[JSON.stringify(params)]
     // hookup success and error
     def.then(success,error)
     return def;
   }
 }
},{})

The following Todo model will never request the same todo twice:

Todo = CachedModel({
 findOne: "/todos/{id}"
},{})

// widget 1
Todo.findOne({id: 5})

// widget 2
Todo.findOne({id: 5})