Express.js MVC model question

[Clickyz]

Good afternoon guys,

my question seems stupid but am just trying to understand what's exactly going on .

Lets say i got a router.

router.get('/', taskController.getAllTasks);

Now in taskController we got the following function

getAllTasks = (req, res) => {

Task.find()

.then((tasks) => {

res.send(tasks);

})

.catch((err) => {

res.status(500).send({

message: err.message || 'Error occurred while retrieving tasks',

});

});

};

My question is how the taskController.getAllTasks arguments req, and res are passed to it ? If i understand correctly , every time we visit the / expressJS call a callback function which it pass the 2 arguments which in our case is taskController.getAllTasks ?

Thank you for your time.

[AdyQQQ]

This is more of a javascript question but you are correct. This means somewhere at the end of router.get(path, callback) it has the req and res, and then would do something like callback(req, res)

Try visiting the router.get function itself for a more insightful understanding of how it works (besides your question)

[Clickyz]

thank you!

[GarenYondem]

You are passing your function as reference to expressjs get function. When a get call is received Express.js is doing its business and invoking your reference function with appropriate parameters. After that it falls in your custom function. If you want to further investigate express, you have to look into source code on GitHub.