Question

When does the callback method in the following piece of code (second parameter of () method) get invoked?

javascript
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('/list', function (req, res) { (generateList()); }
Option 1: When the server is created
Option 2: When a request is made to '/list'
Option 3: When generateList() is called
Option 4: When the response is sent

Answer 1

The callback method in the given code gets invoked when a request is made to '/list'. The callback function is responsible for generating the list and it is executed as a response to the client's request.

Step-by-step explanation:

The callback method in the given code gets invoked when a request is made to '/list'. In this code, the server listens for a request made to the '/list' URL and when it receives a request, it invokes the callback function provided as the second parameter of the () method.

The callback function is executed when the server receives a request and is responsible for generating the list by calling the generateList() function. It is important to note that the callback function is not automatically invoked when generateList() is called directly.

The callback function is part of the request-response cycle in Node.js, where it is executed as a response to a client's request. Once the callback function has generated the list, the server sends the response back to the client using the res parameter.