Reactのライフサイクル

/**
 * ------------------ The Life-Cycle of a Composite Component ------------------
 *
 * - constructor: Initialization of state. The instance is now retained.
 *   - componentWillMount
 *   - render
 *   - [children's constructors]
 *     - [children's componentWillMount and render]
 *     - [children's componentDidMount]
 *     - componentDidMount
 *
 *       Update Phases:
 *       - componentWillReceiveProps (only called if parent updated)
 *       - shouldComponentUpdate
 *         - componentWillUpdate
 *           - render
 *           - [children's constructors or receive props phases]
 *         - componentDidUpdate
 *
 *     - componentWillUnmount
 *     - [children's componentWillUnmount]
 *   - [children destroyed]
 * - (destroyed): The instance is now blank, released by React and ready for GC.
 *
 * -----------------------------------------------------------------------------
 */

参考: Should I use React.createClass, ES6 Classes or stateless functional components? – James K Nelson

react-routerでURLにアクセスできない

webpack-dev-serverを使っている場合

webpack-dev-serverコマンドに--history-api-fallbackオプションが付いているかを確認しましょう。

参考

react-router-redux で URL 直打ちすると Cannot GET /subdir になる – Qiita