sui-react-initial-props

> Make your React pages to get initial props asynchronously both client and server

Motivation

sui-react-initial-props offers a way to make your easily your app isomorphic.

- Offers same parameters for your getInitialProps in the client in the server to make your app 100% universal.
- Avoid re-renders as other options like React-Transmit causing a longer time to respond, specially in the server.
- Minimal footprint by focusing on the really need stuf.

![example]

Usage

``js
import loadPage from '@s-ui/react-initial-props/lib/loadPage'

// Optional logger for error handling
const logger = {
error: (message, error) => {
console.error(message, error)
// Send to your logging service
}
}

// use the loadPage from the sui-react-initial-props
const loadHomePage = loadPage(
() => import(/ webpackChunkName: "HomePage" / './pages/Home'),
logger // optional: for server-side error logging
)

export default (



)
`

`js
// server - isomorphic middleware

import {
createServerContextFactoryParams,
ssrComponentWithInitialProps
} from '@s-ui/react-initial-props'

function isomorphic (req, res, next) {
contextFactory(
createServerContextFactoryParams(req) // pass the request to create the context
).then(context => {
match({routes, location: req.url}, function (error, redirectLocation, renderProps = false) {
const Target = (props) =>


ssrComponentWithInitialProps({ context, renderProps, Target })
.then(({ initialProps, reactString, performance }) => {
// you have here the initialProps retrieved from the page in case you need it
console.log('Time spent resolving the getInitialProps method', performance.getInitialProps)
console.log('Time spent rendering the react tree', performance.renderToString)
res.send(reactString)
})
}
`

`js
universal - react page component

const Page = (props) => {
useEffect(()=> {
// If defined previously as seen below, access __HTTP__ object as follows:
const {initialContent, __HTTP__} = props
const {redirectTo} = __HTTP__
window.location.href = redirectTo
})

return (


)
}

Page.getInitialProps = ({ context, routeInfo }) =>
Promise.resolve({
initialContent: 'This is the initial content',
// Optional __HTTP__ object to perform 301 Redirects
__HTTP__: {
redirectTo: 'https://<301 Redirect Route>',
// Optional object to set an Http-Cookie before redirection
httpCookie: {
AdNotAvailable: true
},
// Optional Array of ojects to set a response headers before redirection
headers: [{'Cache-Control': 'no-store, max-age=0'}]
}
})
/**
* Determine if Page should be kept while navigating on client between routes for the same page.
* If true, while getting intial props on client, the component will receive a isLoading prop.
* If false, a renderLoading method could be used in order to render a placeholder while loading.
* If no value is provided, false is used.
**/
Page.keepMounted = true

/**
* This could be used only in case you are using keepMounted with a false value.
* This will be rendered while fetching getInitialProps on the client.
**/
Page.renderLoading = () =>

Loading...


`

Installation

`sh
npm install @s-ui/react-initial-props --save
`

API Reference

#### createClientContextFactoryParams()

Create the params for the contextFactory on the client

##### Response

| Field | Type | Description |
| --------- | --------- | ------------------------------------------------------------- |
| cookies | string | All the cookies of the user |
| isClient | boolean | Useful to know in your contextFactory if you're in the client |
| pathName | string | Current path of the url requested |
| userAgent | string | Information of the browser, device and version in raw |

#### createServerContextFactoryParams({ req })

Create the params for the contextFactory on the server

##### Params

| Field | Type | Description |
| ----- | -------- | ------------------------------------------------------------------------------------------------------------------------------------------------------ |
| req | object | Native Node Incoming Message with any customized property added on your middleware |

##### Response

| Field | Type | Description |
| --------- | --------- | ------------------------------------------------------------------------------------------------------------------------------------------------------ |
| cookies | string | All the cookies of the user |
| isClient | boolean | Useful to know in your contextFactory if you're in the client |
| pathName | string | Current path of the url requested |
| req | object | Native Node Incoming Message with any customized property added on your middleware |
| userAgent | string | Information of the browser, device and version in raw |

#### ssrComponentWithInitialProps({ Target, context, renderProps })

This method, retrieves the component page with the getInitialProps method, executes the async method and when it receives the info, then render to a string using the Target component and passing down the context.

##### Params

| Field | Type | Description |
| ----------- | --------------- | -------------------------------------------------------------------------------------------- |
| Target | React Element | React Element to be used for passing the context and render the app on it. |
| context |  object | Context to be passed to the Target component and to the getInitialProps |
| renderProps | object | Props used by React Router with some useful info. We're extracting the pageComponent from it |

##### Response

The response is a promise resolved with two parameters. In addition, you can define an optional __HTTP__ object in initialProps to allow server side redirects using SUI-SSR:

| Field | Type | Description |
| --------------------- | -------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| initialProps | object | Result of executing the getInitialProps of the pageComponent. |
| initialprops.HTTP | object | An optional object containing a redirectTo key where an url might be included to allow 3XX server side redirects using [sui-ssr]. By default, redirect status code is 301, but you may set a valid redirectStatusCode option set in the file @s-ui/ssr/status-codes, an optional httpCookie key where you will define an object with the key/value of the Http-Cookie to be set from server and an optional headers key array of objects where you will define a custom response headers (see https://github.com/SUI-Components/sui/tree/master/packages/sui-ssr) |
| reactString | string | String with the renderized app ready to be sent. |

#### loadPage(importPage, logger?)

Load the page asynchronously by using React Router and resolving the getInitialProps. On the client it prepare the component to show the renderLoading (if specified) of the component. On the server, it wraps getInitialProps execution in a try-catch block to prevent crashes.

##### Params

| Field | Type | Description |
| ---------- | ------------------- | ---------------------------------------------------------------------------------------------------------- |
| importPage | function | Import the chunk of the page |
| logger | object (optional) | Optional logger object with an error(message: string, error: Error) method for server-side error logging |

##### Error Handling

When getInitialProps throws an error on the server:

- The error is caught, logged using the provided logger (if available), and then re-thrown.
- This allows the server's global error handling middleware to catch the exception and manage the response accordingly (e.g., render a 500 page), preventing the SSR process from crashing silently.

Example logger implementation:

`js
const logger = {
error: (message, error) => {
console.error(message, error)
// Send to Sentry, DataDog, etc.
}
}
``

Contributing

Please refer to the main repo contributing info.