I build an api rest by express js simply to post an data in my server .
app.post("/register", function(request, response){
var username = request.body.username;
});
How i can do this with feathersjs ? and how i can call it from my reactjs app ?
Feathers is a drop-in replacement for Express. That means you can replace your const app = express();
with const app = feathers()
and everything will work just the same, so what you are showing above you can also do with Feathers.
The real Feathers way to accomplish this however is through services which - with the other important concepts - are described in the basics guide.
There are pre-build services for several databases (which can be customized through hooks) but you can always create your own service. It is important to note that Feathers services - unlike the Express middleware you showed - will be available via HTTP (REST) and websockets (which also gets you real-time events). See here how service methods map to REST endpoints.
Your example in Feathers simply looks like this:
app.use('/register', {
create(data, params) {
// data is the request body e.g.
// data.username
// Always return a promise with the result data
return Promise.resolve(data);
}
});