JoaoCnh

const songs = [
  {
    id: 1,
    name: "Curl of the Burl",
    artist: "Mastodon",
  },
  {
    id: 2,
    name: "Oblivion",
    artist: "Mastodon",

JoaoCnh

var allSongNames = songs.map(function (song) {
  return song.name;  
});

// ES6
const allSongNames = songs.map(song => {
  return song.name;
});

console.log(allSongNames); // ["Curl of the Burl","Oblivion","Flying Whales","L'Enfant Sauvage"];

JoaoCnh

class Mouse extends React.Component {
  constructor(props) {
    super(props);
    this.handleMouseMove = this.handleMouseMove.bind(this);
    this.state = { x: 0, y: 0 };
  }

  handleMouseMove(event) {
    this.setState({
      x: event.clientX,

JoaoCnh

@withI18n
class MyComponent extends Component {
  render() {
    return <div>{this.props.locale}</div> 
  }
}

// or -- depending on your decorator usage

class MyComponent extends Component {

JoaoCnh

import React, { Component } from "react";
import PropTypes from "prop-types";

const withI18n = ComponentToWrap => {
  return class I18nComponent extends Component {
    static contextTypes = {
      t: PropTypes.func.isRequired,
      locale: PropTypes.string.isRequired
    };

JoaoCnh

import React, { Component } from "react";
import PropTypes from "prop-types";
import Polyglot from "node-polyglot";

// for example
import translations from "../my-translations.json";

class I18nProvider extends Component {
  static propTypes = {
    locale: PropTypes.string.isRequired,

JoaoCnh

import React from "react";

export default class Avatar extends React.Component {
  state = {
    open: false,
  };

  shouldComponentUpdate(nextProps, nextState) {
    const photoChanged = this.props.avatarUrl !== nextProps.avatarUrl;
    const optionsWereToggled = this.state.open !== nextState.open;

JoaoCnh

import React from "react";
import { Formik, Form, Field } from "formik";
import yup from "yup";

class Form extends React.Component {
  state = { error: false };
  
  _submit = async (values, { setSubmitting }) => {
    // build form data
    const formData = new FormData();

JoaoCnh

import React from "react";
import PropTypes from "prop-types";

class AjaxForm extends React.Component {
  static propTypes = {
    type: PropTypes.string.isRequired,
    url: PropTypes.string.isRequired,
    onSuccess: PropTypes.func.isRequired,
  };

JoaoCnh

<List 
  url="https://api.github.com/users/JoaoCnh/repos"
  render={({ list, isLoading }) => (
    <div>
      <h2>My repos</h2>
      {isLoading && <h2>Loading...</h2>}

      <ul>
        {list.length > 0 && list.map(repo => (
          <li key={repo.id}>