從構造函數實例化的全範圍對象

Question

在下面的一些API中，它需要我想在構造函數中動態分配的憑據。然後我想在整個班級中使用一些API。即在下面的例子中someMethodUsingSomeAPI是一個幫助方法，我想從B的一個實例中的其他方法中調用。這對Coffee-/JavaScript來說可能嗎？ （我可以讓它開始工作的唯一方法是，如果我把someMethodUsingSomeAPI在構造函數中。）

SomeAPI = Npm.require 'someAPI' 

class B extends A 
    constructor: (options = {}) -> 
    unless @ instanceof B 
     return new B(options) 

    @config = JSON.parse(Assets.getText('config/' + options.username + '.json')) 

    @someAPI = new SomeAPI 
     consumer_key: @config.credentials.consumer.key 
     consumer_secret: @config.credentials.consumer.secret 
     access_token: @config.credentials.access.token 
     access_token_secret: @config.credentials.access.secret 

    someMethodUsingSomeAPI = Async.wrap((id, callback) -> 
    return @someAPI.get 'whatever/show', { 'id': id }, callback 
) 

    console.log someMethodUsingSomeAPI '123' # Error: Cannot call method 'get' of undefined 

已更新，建議從saimeunt

... 

someMethodUsingSomeAPI = (id) -> 
    wrappedGet = Async.wrap(@someAPI, 'get') 
    wrappedGet 'whatever/show', { id: id } 

console.log someMethodUsingSomeAPI '123' # ReferenceError: someMethodUsingSomeAPI is not defined 

&

b = B('username') 
b.someMethodUsingSomeAPI '123' # Works! 

更改someMethodUsingSomeAPI:到someMethodUsingSomeAPI =

console.log someMethodUsingSomeAPI '123' # Error: unsupported argument list 

&

b = B('username') 
b.someMethodUsingSomeAPI '123' # TypeError: Object #<B> has no method 'someMethodUsingSomeAPI' 

（這與流星0.9.3.1）

UPDATE IN試圖澄清

Here's a simplified version of the above, without any of the API stuff.

someMethod = works，someMethod: doesn't work

我很高興classInstance.someMethod在使用時有效，但真的很想讓它在實際情況下工作。

Answer 1

當然，您可以將someAPI附加到您的類對象上。在咖啡標@用於代替this（因爲它會在Javscript中）。

SomeAPI = require 'someAPI' 

class A extends B 
    constructor: (options = {}) -> 
    unless @ instanceof A 
     return new A(options) 

    @config = JSON.parse('config/' + options.username + '.json') 

    @someAPI = new SomeAPI 
     consumer_key: @config.credentials.consumer.key 
     consumer_secret: @config.credentials.consumer.secret 
     access_token: @config.credentials.access.token 
     access_token_secret: @config.credentials.access.secret 

    someMethodUsingSomeAPI: (id, callback) -> 
    return @someAPI.get 'whatever/show', { 'id': id }, callback 

你可以看看this SO question這也解釋了JavaScript的this，其範圍。一旦你明白了，看看coffeescript's classes是如何工作的，你應該對@的使用有一定的瞭解。

Answer 2

我想這是你想要什麼：

someMethodUsingSomeAPI:function(id){ 
    var wrappedGet=Async.wrap(@someAPI,"get"); 
    return wrappedGet("whatever/show",{ 
    id:id 
    }); 
}