Code comments for lazy method

lib/lazy.js

@@ -12,6 +12,17 @@ const {createElement} = require('react');
 const isServer = typeof window === 'undefined';
 const fatalPromise = {then: () => {}, _fatal: true};
 
+/**
+ * Create a lazy-loaded component, to work with `React.Suspense`.
+ * When returned component is first rendered, it calls `ctor()` which should return a Promise.
+ * Component throws the Promise.
+ * Once promise resolves, further renders will render the loaded component.
+ *
+ * @param {Function} ctor - Function to call to load component. Must return a Promise.
+ * @param {Object} [options] - Options object
+ * @param {boolean} [options.ssr = true] - If falsy then component will not be rendered on server
+ * @returns {Function} - Lazy component
+ */
 module.exports = function lazy(ctor, options) {
 	let noSsr = options ? options.ssr !== undefined && !options.ssr : false;