How to collect user input for retrieving data in reactjs?

Question

I was able to get all users and (through button clicks) to get a particular user by id. But I cannot figure out a way to get a user from an input.

Can anybody please suggest how to achieve that?

This is my code:

import React, {Component} from 'react'

class App extends Component {

    constructor(props){
        super(props)
        this.onHandleUsers = this.onHandleUsers.bind(this)
        this.state = {
            isLoaded: false,
            users: []
        }
    }
    onHandleUsers() {
        fetch("http://localhost:3000/api/users")
        .then(res => res.json())
        .then(result => {
            this.setState({
                isLoaded: true,
                users: result
            })
        })
        .catch(e => console.log(e))
    }

    onHandleCurrentUsers(userId) {
        const data = {userId: userId}
        fetch("http://localhost:3000/api/user", {
            method: 'POST',
            headers: { "Content-Type": "application/json"},
            body: JSON.stringify(data)
        })
        .then(res => res.json())
        .then(result => {
            this.setState({
                isLoaded: false,
                currentUser: result
            })
        })
        .catch(e => console.log(e))
    }




    render() {
        const {currentUser} = this.state
        return (
            <div>

                <button onClick={this.onHandleUsers}>Gauti vartotojus</button>
                <ul>
                    {
                        this.state.isLoaded && this.state.users.map(item => {
                            return (
                                <li>name : {item.name} <br> 
                                </br>surname: {item.surname}</li>
                        )
                        })
                    }

                </ul>
                <button onClick ={e => this.onHandleCurrentUsers(1)}>get first user </button>
                <button onClick ={e => this.onHandleCurrentUsers(2)}>get second user </button>
                <div>
                    {
                        currentUser && <div>{currentUser.name} {currentUser.surname}</div>
                    }
                </div>

                <div>  </div>
        </div>
        )
    }
}

export default App

Answer 1

it's fairly simple, all you have to do is to have an input that handles the desired user's id:

<input name='userId' onChange={this.handleUserChange} />

and we define this.handleUserChange like this:

handleUserChange = (e) => {
  const {value} = e.target

  this.onHandleCurrentUsers(value)
}

and basically you pass the id of a user to our input and it changes the current user!

Answer 2

Hello this is indeed helpful, but i already had this one done, thing is with this one it instantly brings the current user on input, my problem is that i have to get a button to click and only then get the value. I m trying to do the same with ref as you did but i cannot bring back ref after my input atm..