How to call a server-side NodeJS function using client-side JavaScript

Question

I'm working on creating a basic login system, and since the server-side uses NodeJS, but client-side doesn't. I have to make any calls that use NPM packages on the server side. The issue is I have no clue how to call a server-side NodeJS function from the Client-Side JavaScript. Basically I wan't to be able to call a function that's stored on the server from the client browser.

Answer 1

Make a route in your nodejs application like so:

app.get('/users', function(req, res) {
 // Your function to be called goes here.
});

Now you can call this code from your client side javascript using ajax. Like this:

$.ajax({
 type: 'GET'
 url: 'http://localhost:8000/users',
 success: function(response) { 
  console.log(response);
 },
 error: function(xhr, status, err) {
   console.log(xhr.responseText);
 }
});

Answer 2

Create a REST API and map the request parameters to the specific function calls you need to use. See this tutorial on creating REST APIs.

Answer 3

You do this by calling APIs on the server (a specific url that will to some specific work).In JS you need ajax. Have a look here

//url be the api like '/api/something/'
$("button").click(function(){
  $.ajax({url: "demo_test.txt", success: function(result){
    // your response
  }});
});

in Node we have axios that will do the same example

axios.post('api/tobackend/function',{user:'a',password:'b'})
     .then((res)=>console.log('response from server'))

in backed you might need route to handle the request.

router.post('api/tobackend/function',(reqs,resp)=>{console.log('backend')})

Answer 4

1. With Socket.io

2. in JS

   let xhr = new XMLHttpRequest(); xhr.open('GET', '/user/sessionDestroy'); xhr.send();

In Node.JS