Fetch: Can you pass parameters to the server - fetch

Question

I'm using a basic fetch to obtain data from an express server that queries the data from a database. So I want to do a login system, i want to send the user/password from the input fields with the fetch request. so i can perform the logical check to see if password matches the data in the server. and respond with the result.
Is it possible to do a fetch that can pass parameters?
Updated Code Below:
let fetchData = {
method: "post",
headers: {
'Accept': 'application/json',
'Content-Type': 'application/json'
},
body: JSON.stringify({
username: this.state.user,
password: this.state.password
})
}
var fromServer = fetch('http://localhost:3000/', fetchData)
.then(function(response){
if( !response.ok){
throw Error (response.statusText);
}
return response.json();
})
.then(function(response) {
console.log(response);
})
.catch(error => console.log("there was an error --> " + error));
Express function
app.post('/', function(req, res){
var uname = req.body.username;
var pw = req.body.password;
console.log(uname);
console.log(pw);
});

Answer 1

Of course you can!
Here is an example of Fetch using a POST request:
fetch("http://example.com/api/endpoint/", {
method: "post",
headers: {
'Accept': 'application/json',
'Content-Type': 'application/json'
},
//make sure to serialize your JSON body
body: JSON.stringify({
name: myName,
password: myPassword
})
})
.then( (response) => {
//do something awesome that makes the world a better place
});
I've answered this question before, check this for more details:
POST Request with Fetch API?
To process the request in Express, as mentioned in your comment assuming your express server is setup to parse body requests, you can do this:
app.post('/your/route', function(req, res) {
var name= req.body.name;
var password = req.body.password;
// ...do your bidding with this data
});