import { createElement } from 'react' import ReactDOM from 'react-dom' import mitt from 'mitt' import HeadManager from './head-manager' import { createRouter } from '../lib/router' import App from '../lib/app' import { loadGetInitialProps, getURL } from '../lib/utils' import ErrorDebugComponent from '../lib/error-debug' import PageLoader from '../lib/page-loader' // Polyfill Promise globally // This is needed because Webpack2's dynamic loading(common chunks) code // depends on Promise. // So, we need to polyfill it. // See: https://github.com/webpack/webpack/issues/4254 if (!window.Promise) { window.Promise = Promise } const { __NEXT_DATA__: { props, err, pathname, query, buildId, assetPrefix }, location } = window const pageLoader = new PageLoader(buildId, assetPrefix) window.__NEXT_LOADED_PAGES__.forEach(({ route, fn }) => { pageLoader.registerPage(route, fn) }) delete window.__NEXT_LOADED_PAGES__ window.__NEXT_REGISTER_PAGE = pageLoader.registerPage.bind(pageLoader) const headManager = new HeadManager() const appContainer = document.getElementById('__next') const errorContainer = document.getElementById('__next-error') let lastAppProps export let router export let ErrorComponent let Component export default async () => { ErrorComponent = await pageLoader.loadPage('/_error') try { Component = await pageLoader.loadPage(pathname) } catch (err) { console.error(`${err.message}\n${err.stack}`) Component = ErrorComponent } router = createRouter(pathname, query, getURL(), { pageLoader, Component, ErrorComponent, err }) const emitter = mitt() router.subscribe(({ Component, props, hash, err }) => { render({ Component, props, err, hash, emitter }) }) const hash = location.hash.substring(1) render({ Component, props, hash, err, emitter }) return emitter } export async function render (props) { // There are some errors we should ignore. // Next.js rendering logic knows how to handle them. // These are specially 404 errors if (props.err && !props.err.ignore) { await renderError(props.err) return } try { await doRender(props) } catch (err) { if (err.abort) return await renderError(err) } } // This method handles all runtime and debug errors. // 404 and 500 errors are special kind of errors // and they are still handle via the main render method. export async function renderError (error) { const prod = process.env.NODE_ENV === 'production' // We need to unmount the current app component because it's // in the inconsistant state. // Otherwise, we need to face issues when the issue is fixed and // it's get notified via HMR ReactDOM.unmountComponentAtNode(appContainer) const errorMessage = `${error.message}\n${error.stack}` console.error(errorMessage) if (prod) { const initProps = { err: error, pathname, query } const props = await loadGetInitialProps(ErrorComponent, initProps) ReactDOM.render(createElement(ErrorComponent, props), errorContainer) } else { ReactDOM.render(createElement(ErrorDebugComponent, { error }), errorContainer) } } async function doRender ({ Component, props, hash, err, emitter }) { if (!props && Component && Component !== ErrorComponent && lastAppProps.Component === ErrorComponent) { // fetch props if ErrorComponent was replaced with a page component by HMR const { pathname, query } = router props = await loadGetInitialProps(Component, { err, pathname, query }) } if (emitter) { emitter.emit('before-reactdom-render', { Component, ErrorComponent }) } Component = Component || lastAppProps.Component props = props || lastAppProps.props const appProps = { Component, props, hash, err, router, headManager } // lastAppProps has to be set before ReactDom.render to account for ReactDom throwing an error. lastAppProps = appProps // We need to clear any existing runtime error messages ReactDOM.unmountComponentAtNode(errorContainer) ReactDOM.render(createElement(App, appProps), appContainer) if (emitter) { emitter.emit('after-reactdom-render', { Component, ErrorComponent }) } }