import React, { useState } from 'react'; import { Collapse } from '@blueprintjs/core'; import classNames from 'classnames'; /** * Postbox. */ export default function Postbox({ defaultOpen = true, toggable = true, title, children, }) { const [isOpen, setIsOpen] = useState(defaultOpen); // Handle the title click. const handleTitleClick = () => { if (toggable) { setIsOpen(!isOpen); } }; return (