Invoke the router function dynamically

Question

Invoke the router function dynamically

I am looking for a way to simplify route registration without manually writing out

app.get('/', function (req, res, next) { });

each time. I want to automate this process by passing in a router object like the one below...

{ 
    path: '',
    method: 'GET',
    function: 'test'
}

Everything works fine until it comes to actually executing the function.

The problem is with how I am attempting to call the function. Instead of executing it, I am only referencing it.

Here is the code responsible for calling the function.

this.routes.forEach((route: IRouter) => {
    const path = this.basePath + '/' + route.path;
    const requestMethod = route.method.toLowerCase();

    this.app[requestMethod](path, this[route.function]());
});

As you can see in the this.app line, I am trying to call the function without passing in necessary parameters like res, req, next.

Is there a way in Express to access these parameters through the app instance, since removing the () from the function call doesn't actually execute it?

Any assistance would be highly appreciated.

javascript typescript express

Answer 1

Answer №1

Depending on the output of this[route.function](), the functionality should work accordingly. For instance, if the test function is defined as follows:

test () {
    return (req, res, next) => {...}
}

Then there should be no issues with it working. However, if the function is structured like this:

test (req, res, next) {...}

In this case, the function should be executed when adding the route handler. If you don't intend to pass any parameters to the functions, it's advisable to go with the second test function and bind it without executing, as shown below:

class Foo () {
  constructor (config) {
    const { basePath } = this

    this.routes.forEach((route: IRouter) => {
      const path = `${basePath}/${route.path}`
      const requestMethod = route.method.toLowerCase()

     this.app[ requestMethod ](path, this[ route.function ].bind(this))
    })
  }

  test (req, res, next) {
    // ...
  }
}

This approach helps in avoiding unnecessary function creation.

Additionally, it's recommended to use fn instead of function in your route object to avoid conflicts with reserved keywords. While it may still function with function, using fn is a safer choice to prevent potential issues.

Answer 2

Depending on the output of this[route.function](), the functionality should work accordingly. For instance, if the test function is defined as follows:

test () {
    return (req, res, next) => {...}
}

Then there should be no issues with it working. However, if the function is structured like this:

test (req, res, next) {...}

In this case, the function should be executed when adding the route handler. If you don't intend to pass any parameters to the functions, it's advisable to go with the second test function and bind it without executing, as shown below:

class Foo () {
  constructor (config) {
    const { basePath } = this

    this.routes.forEach((route: IRouter) => {
      const path = `${basePath}/${route.path}`
      const requestMethod = route.method.toLowerCase()

     this.app[ requestMethod ](path, this[ route.function ].bind(this))
    })
  }

  test (req, res, next) {
    // ...
  }
}

This approach helps in avoiding unnecessary function creation.

Additionally, it's recommended to use fn instead of function in your route object to avoid conflicts with reserved keywords. While it may still function with function, using fn is a safer choice to prevent potential issues.

Invoke the router function dynamically

Answer №1

Similar questions

What factors outside of the program could potentially lead to the splice function not functioning as expected?

Removing an item from an ng-repeat loop while also dealing with a FormController within

Having issue with jQuery popup not functioning correctly on the right side with the contact form. Is there anyone who knows how

Which is the best choice for a large-scale production app: caret, tilde, or a fixed package.json

Adjusting the rotation transform by deleting and reapplying canvas is causing the chart to not display data after redrawing

Problem with selecting odd and even div elements

When selecting an old list, only the most recently created ID is displayed, rather than the ID of the specific list being

Keep the sub-menu in a kendo context menu from closing until the user either hovers over another menu item or clicks outside of the current item

How to Share Your Vuejs Component with the World by Publishing it on npm

Difficulty encountered when consolidating intricate data attributes into a single array

Embed a javascript tag to print a PDF document

A guide on importing gLTF files into three.js

Callbacks for AJAX responses that are asynchronous

Bar chart in Chart.js becomes crowded and illegible on smaller screens due to overlapping bars

Encountering an issue: Unable to initiate a local server when running `npm start`

An issue occurred with building deployments on Vercel due to a typing error

What is the best way to link function calls together dynamically using RXJS?

How can you use CSS animations to animate two images in a way that hides one while showing the other?

Leveraging the replace feature within Selenium IDE

Creating a personalized to-do list feature in NodeJs for exclusive user access: A step-by-step guide