Form Handling in Controlled way or React way

import React, { Component } from 'react'

class Form extends Component {
    constructor(){
        super()
        this.state = {
            email: "", //-------- (5)
            password: "",
            hobby: [] //--------- (12)
        }
    } //--------- (4)

    //input Handler
    inputHandler = (e) => {
        this.setState({
            [e.target.name] : e.target.value //store the value of the input in state value and update the state value ------------ (3)
        })
    } // ---------- (2)

    //hobbyController
    hobbyController = (e) => {
        if(e.target.checked){          {/* -------- (9) */ }
            this.setState({
                hobby : [...this.state.hobby, e.target.value]  //-------- (11)
            })
        }else if(e.target.checked == false){  {/* -------- (10) */ }
            let index = this.state.hobby.findIndex(ele => ele == e.target.value)
            this.state.hobby.splice(index, 1)  //-------- (13)
        }
    } //----------------- (8)

    //submitHandler
    submitHandler = (e) => {
        e.preventDefault() //to avoid auto page load during submission ------------------ (16)
        let {email, password, hobby} = this.state //get the data from state  -------------- (17)
        console.log(`Email: ${email}
                    Password: ${password}
                    Hobby: ${hobby}`);
    } // -------------- (15)

    render() {
        return (
            <form>
                {/* email  */}
                <div className="form-group">
                    <label htmlFor="exampleInputEmail1">Email address</label>
                    <input type="email" className="form-control" id="exampleInputEmail1" aria-describedby="emailHelp" placeholder="Enter email" name = "email" value = {this.state.email} onChange = {this.inputHandler}></input> {/* ---------- (1) */}
                </div>

                {/* password  */}
                <div className="form-group">
                    <label htmlFor="exampleInputPassword1">Password</label>
                    <input type="password" className="form-control" id="exampleInputPassword1" placeholder="Password" name = "password" value = {this.state.password} onChange ={this.inputHandler}></input>
                </div>


                {/* hobby  */}
                <label htmlFor="hobby">Hobby</label>
                    {/* drawing  */}
                <div className="form-check">
                    <input type="checkbox" className="form-check-input" id="exampleCheck1" name = "hobby" value = "drawing" onChange = {this.hobbyController}></input> {/* ---------- (7) */}
                    <label className="form-check-label" htmlFor="Drawing">Drawing</label>
                </div>
                    {/* playing  */}
                <div className="form-check">
                    <input type="checkbox" className="form-check-input" id="exampleCheck1" name = "playing" value = "playing" onChange = {this.hobbyController}></input> {/* ---------- (6) */}
                    <label className="form-check-label" htmlFor="Playing">Playing</label>
                </div>

                {/* submit  */}
                <button type="submit" className="btn btn-primary" onClick = {this.submitHandler} >Submit</button> {/* ---------- (14) */}
            </form>
        )
    }
}

export default Form