MealPlan.js

import React, { Component } from 'react';
import _ from 'lodash';

class MealPlan extends Component {
  state = {
    meal: '',
    meals: []
  };

  renderMeals() {
    return _.map(this.state.meals, meal => <li>{meal}</li>);
  }

  render() {
    return(
      <div>
        <h2>Today you should eat this</h2>
        <input
          onChange={e => this.setState({meal: e.target.value})}
          value={this.state.meal}
          type="text"
        />
        <button
          onClick={() => this.setState({meals: [...this.state.meals, this.state.meal]})}>
          Add meal</button>
        <ul>
          {this.renderMeals()}
        </ul>
      </div>
    );
  }
}

export default MealPlan;