a React propTypes example

FeatureItem.jsx

import React, { Component } from 'react';
import slugify from 'slugify';
import pTypes from 'prop-types';

// This object will allow us to
// easily convert numbers into US dollar values
// React propTypes
const USCurrencyFormat = new Intl.NumberFormat('en-US', {
    style: 'currency',
    currency: 'USD'
});

export default class FeatureItem extends Component {

    static propTypes = {
        //unique id
        id: pTypes.string.isRequired,
        onChange: pTypes.func.isRequired,
        //displayed name
        name: pTypes.string,
    }

    render() {
        const { id, name, checked, onChange } = this.props
        return (
            <div key={id} className="feature__item">
                <input
                    type="radio"
                    id={id}
                    className="feature__option"
                    name={name}
                    checked={checked}
                    onChange={onChange}
                />
                <label htmlFor={id}
                    className="feature__label">
                    {this.props.item.name} ({USCurrencyFormat.format(this.props.item.cost)})
                </label>
                <Greeting name={'Seth'} age={32}  />
            </div>
        );
    }
}

function Greeting({name, age}) {
    return <p>{`Hello, ${name} , ${age}`}</p>
}

Greeting.propTypes = {
    name: pTypes.string.isRequired,
    age: pTypes.number.isRequired,
}