source: my-react-app/src/components/LoginForm.js

import * as React from "react";
import bootstrap from 'bootstrap/dist/css/bootstrap.min.css'
import classNames from 'classnames';

export default class LoginForm extends React.Component {
    constructor(props) {
        super(props);
        this.state = {
            active: "login",
            firstName: "",
            lastName: "",
            email: "",
            password: "",
            onLogin: props.onLogin,
            onRegister: props.onRegister
        }
    }

    onChangeHandler = (e) => {
        let name = e.target.name;
        let value = e.target.value;
        this.setState({[name]: value})
    }

    onSubmitLogin = (e) => {
        this.state.onLogin(e, this.state.email, this.state.password);
    }

    onSubmitRegister = (e) => {
        this.state.onRegister(
            e,
            this.state.firstName,
            this.state.lastName,
            this.state.email,
            this.state.password)
    }

    render() {
        return (
            <div className="row justify-content-center">
                <div className="col-4">
                    <ul className="nav nav-pills nav-justified mb-3" id="ex1" role="tablist">
                        <li className="nav-item" role="presentation">
                            <button className={classNames("nav-link", this.state.active === "login" ? "active" : "")}
                                    id="tab-login" onClick={() => this.setState({active: "login"})}>Login
                            </button>
                        </li>
                        <li className="nav-item" role="presentation">
                            <button className={classNames("nav-link", this.state.active === "register" ? "active" : "")}
                                    id="tab-register" onClick={() => this.setState({active: "register"})}>Register
                            </button>
                        </li>
                    </ul>

                    <div className="tab-content">
                        <div
                            className={classNames("tab-pane", "fade", this.state.active === "login" ? "show active" : "")}
                            id="pills-login">
                            <form onSubmit={this.onSubmitLogin}>
                                <div className="form-outline mb-4">
                                    <input type="email" id="email" name="email" className="form-control"
                                           onChange={this.onChangeHandler}/>
                                    <label className="form-label" htmlFor="email">Email</label>
                                </div>
                                <div className="form-outline mb-4">
                                    <input type="password" id="loginPassword" name="password" className="form-control"
                                           onChange={this.onChangeHandler}/>
                                    <label className="form-label" htmlFor="loginPassword">Password</label>
                                </div>

                                <button type="submit" className="btn btn-primary btn-block mb-4">Sign In</button>
                            </form>
                        </div>

                        <div
                            className={classNames("tab-pane", "fade", this.state.active === "register" ? "show active" : "")}
                            id="pills-register">
                            <form onSubmit={this.onSubmitRegister}>
                                <div className="form-outline mb-4">
                                    <input type="text" id="firstName" name="firstName" className="form-control"
                                           onChange={this.onChangeHandler}/>
                                    <label className="form-label" htmlFor="firstName">First Name</label>
                                </div>
                                <div className="form-outline mb-4">
                                    <input type="text" id="lastName" name="lastName" className="form-control"
                                           onChange={this.onChangeHandler}/>
                                    <label className="form-label" htmlFor="lastName">Last Name</label>
                                </div>
                                <div className="form-outline mb-4">
                                    <input type="email" id="email" name="email" className="form-control"
                                           onChange={this.onChangeHandler}/>
                                    <label className="form-label" htmlFor="email">Email</label>
                                </div>
                                <div className="form-outline mb-4">
                                    <input type="password" id="loginPassword" name="password" className="form-control"
                                           onChange={this.onChangeHandler}/>
                                    <label className="form-label" htmlFor="loginPassword">Password</label>
                                </div>

                                <button type="submit" className="btn btn-primary btn-block mb-4">Register</button>
                            </form>
                        </div>
                    </div>
                </div>
            </div>
        );

    }
}