如何在Lo-Dash中使用thisArg？

Question

如何在Lo-Dash中使用thisArg？有沒有可能將它與鏈接結合起來？這是一個使用thisArg從他們的文檔的例子：

_.map(collection, [callback=identity], [thisArg]) 

Creates an array of values by running each element in the collection through the callback. The callback is bound to thisArg and invoked with three arguments; (value, index|key, collection). 

If a property name is provided for callback the created "_.pluck" style callback will return the property value of the given element. 

If an object is provided for callback the created "_.where" style callback will return true for elements that have the properties of the given object, else false. 

Aliases 

_.collect 

Arguments 

collection (Array|Object|string): The collection to iterate over. 
[callback=identity] (Function|Object|string): The function called per iteration. If a property name or object is provided it will be used to create a ".pluck" or ".where" style callback, respectively. 
[thisArg] (*): The this binding of callback. 
Returns 

(Array): Returns a new array of the results of each callback execution. 

一個例子，將不勝感激，因爲我無法找到任何自己的文檔。

Answer 1

參數thisArg只是指向this指向調用方的上下文，該上下文也將用作回調的上下文。它提供了方便。

結果是一樣的，如果使用本機Function.bind()方法例如爲：

_.map(collection, callback.bind(this)); 

另一種方法將是使的this別名變量，並用它來代替。