React Form: fetching data entered by user

I’m working on a SignUp Form, I’m trying to fetch the data entered by the user but for some reason I’m getting just null values, like the next example:

So, for the task I’m using two components, Signup and Input, the bellow code is from Signup.js:

import React, { useContext, useState, useRef } from "react";
import Modal from "../UI/Modal";
import classes from "./Login.module.css";
import Input from "../UI/Input/Input";

const Signup = (props) => {
  const firstnameInputRef = useRef();
  const lastnameInputRef = useRef();
  const emailInputRef = useRef();
  const passwordInputRef = useRef();

  const [isCanceling, setIsCanceling] = useState(false);
  const [isSaving, setIsSaving] = useState(false);
  const [didSave, setDidSave] = useState(false);
  const [isErrorOnSave, setIsErrorOnSave] = useState(false);
  //const cartCtx = useContext(CartContext);

  const errorOnSignupHandler = () => {
    setIsErrorOnSave(true);
  };

  const signupHandler = async (clientData) => {
    setIsSaving(true);
    const enteredFirstname = firstnameInputRef.current.value;
    const enteredLastname = lastnameInputRef.current.value;
    const enteredEmail = emailInputRef.current.value;
    const enteredPassword = passwordInputRef.current.value;

    const newClientData = {
      firstname: enteredFirstname,
      lastname: enteredLastname,
      email: enteredEmail,
      password: enteredPassword,
    };

    console.log(newClientData);

    const response = await fetch("http://localhost:3000/clients", {
      method: "POST",
      headers: {
        "Content-Type": "application/json",
      },
      body: JSON.stringify(newClientData),
    });

    if (!response.ok) {
      errorOnSignupHandler();
    } else {
      setIsSaving(false);
      setIsCanceling(false);
      setDidSave(true);
      //cartCtx.clearCart();
    }
  };

  const isSavingModalContent = <p>Saving new user...</p>;
  /* incluir transaccion para verificar si es exitoso o hubo algun error */

  const errorOnSavingModalContent = (
    <React.Fragment>
      <p>The user account could not be created. Please try again later</p>
      <div className={classes.actions}>
        <button className={classes.button} onClick={props.onClose}>
          Close
        </button>
      </div>
    </React.Fragment>
  );

  const didSaveModalContent = (
    <React.Fragment>
      <p>User account created, welcome!</p>
      <div className={classes.actions}>
        <button className={classes.button} onClick={props.onClose}>
          Close
        </button>
      </div>
    </React.Fragment>
  );

  const SignupButtons = (
    <React.Fragment>
      <button className={classes["button--alt"]} onClick={signupHandler}>
        Sign-Up
      </button>
      <button className={classes["button--alt"]} onClick={props.onClose}>
        Close
      </button>
    </React.Fragment>
  );

  const modalActions = (
    <div className={classes.actions}>{!isCanceling ? SignupButtons : ""}</div>
  );

  const SignupModalContent = (
    <React.Fragment>
      <Input
        ref={firstnameInputRef}
        id="firstname"
        label="First Name"
        type="text"
        //isValid={emailIsValid}
        //value={emailState.value}
        //onChange={emailChangeHandler}
        //onBlur={validateEmailHandler}
      />
      <Input
        ref={lastnameInputRef}
        id="lastname"
        label="Last Name"
        type="text"
        //isValid={emailIsValid}
        //value={emailState.value}
        //onChange={emailChangeHandler}
        //onBlur={validateEmailHandler}
      />
      <Input
        ref={emailInputRef}
        id="email"
        label="E-Mail"
        type="email"
        autodata="off"
        //isValid={emailIsValid}
        //value={emailState.value}
        //onChange={emailChangeHandler}
        //onBlur={validateEmailHandler}
      />
      <Input
        ref={passwordInputRef}
        id="paswword"
        label="Password"
        type="password"
        autodata="new-password"
        //isValid={passwordIsValid}
        //value={passwordState.value}
        //onChange={passwordChangeHandler}
        //onBlur={validatePasswordHandler}
      />
      <Input
        //ref={passwordInputRef}
        id="paswword2"
        label="Confirm-Password"
        type="password"
        autodata="new-password"
        //isValid={passwordIsValid}
        //value={passwordState.value}
        //onChange={passwordChangeHandler}
        //onBlur={validatePasswordHandler}
      />
      {modalActions}
    </React.Fragment>
  );

  return (
    <Modal onClose={props.onClose}>
      {!isCanceling && !isSaving && !isErrorOnSave && !didSave && SignupModalContent}
      {isSaving && isSavingModalContent}
      {isErrorOnSave && errorOnSavingModalContent}
      {!isSaving && didSave && didSaveModalContent}
    </Modal>
  );
};

export default Signup;

And this is the code from Input.js:

import React from 'react';
import classes from './Input.module.css';

const Input = React.forwardRef((props, ref) => {
    return(
        <div className={classes.input}>
            <label htmlFor={props.input.id}>{props.label}</label>
            <input ref={ref} {...props.input}/>
        </div>
    );
});

export default Input;

well, basically my question is what am I missing to the get the input data from the user?

Thanks a lot for your comments.

>Solution :

You generally shouldn’t use refs the way you’re using them.

Instead, have a state for each input, and have the input value equal to the state. When the input changes, update the state.

This way, the state always reflects the state of the form, and is synced up with it. It’s a patter called "controlled components". See here for more details.