React Data SSR

This package provides a High Order Component to make SSR and data fetching painless.

Instalation

yarn -i react-data-ssr
 
# Or using npm 
npm -i react-data-ssr --save

Examples

The examples folder contains several exmaples.

---

• Usage
  • Simple Example
• Api
  • withGetInitialData(options)
    • options
      • getData: (props: Object, bag: Object) => Promise
      • mapDataToProps: (data: Object, ownProps: Object) => Object
      • mapArgsToProps?: (branch: Object, extra?: Object) => Object (optional)
      • shouldGetData?: (props: Object, nextProps: Object) => boolean (optional)
      • generateComponentKey?: (component: ReactComponent, props: Object) => String (optional)
    • Injected props and methods
    • Props
  • <WithGetInitialDataComponent />
    • Props
      • getInitialData: (key: String) => Object
      • hasLoadedComponent: (key: String) => bool
      • dismissLoadedComponent: (key:String) => null
    • Methods
      • static getInitialData(branch?: Object, extra?: Object) => {key: String, promise: Promise}

Usage

Simple Example

// List.js
import React from 'react';
import PropTypes from 'prop-types';
import { withGetInitialData } from 'react-data-ssr';
 
const List = ({isLoading, list}) => {
  if (isLoading)
    return <span>Loading</span>;
  return (
    <div>
      <h1>List</h1>
      <ul>
        {(list||[]).map((l, i) => <li key={i}>${l}</li>)}
      </ul>
    </div>
  );
};
 
List.propTypes = {
  isLoading: PropTypes.bool,
  list: PropTypes.array,
};
 
// This function is used to map the data setted by `setData` to the component properties
const mapDataToProps = ({data}) => ({
  list: data,
});
 
// This function will be incharge of fetching the data
// `props` are the component properties
const getData = (props, {setLoading, setData}) => new Promise(rs => {
  // Set the loading state
  setLoading(true);
 
  // Pretend we are doing something async
  setTimeout(() => {
    // Sets the data, it also sets the loading state to false
    setData({
      data: [
        'first',
        'second',
        'thrid',
      ]
    });
    rs();
  }, 1000);
});
 
export default withGetInitialData({
  mapDataToProps,
  getData,
})(List);
 
// client.js
import { hydrate } from 'react-dom';
import List from './List';
 
const data = window.__INITIAL_DATA__; // Server Side Rendered data
hydrate(
  <List
    hasLoadedComponent={k => k in data}
    dismissLoadedComponent={k => delete data[k]}
    getInitialData={k => data[k]}
  />,
  document.getElementById('root')
);

Note: The example uses React 16, but it's not a requeriment. React 15 could alse be used.

Api

withGetInitialData(options)

Create a high-order React component class that fetches data server side and re uses the data in client side (or fetches it if it isn't available).

options

getData: (props: Object, bag: Object) => Promise

This function is called to perform the fetch of the data.

• props: The component properties, on server side they are created by mapArgsToProps function.
• bag: An object with two methods:
  • setLoading: (b: bool) => null: To set the isLoading property.
  • setData: (data: Object) => null: To set the data, it will set isLoading to false.

Note: Server and client will call the same function, in order to provide different data fetching logic, one could use Webpack's Normal Module Replacement Plugin and implement a package with the same inteface.

Note: This function is required

mapDataToProps: (data: Object, ownProps: Object) => Object

This function is used to map the data fetched to component properties.

The result of this function must be a plain object that will be merged to the component's props.

• data: Is the data object setted with the setData function in the getData phase.
• ownProps: Is an object with the props of the component

Note: This function is required

mapArgsToProps?: (branch: Object, extra?: Object) => Object (optional)

This function is used to build the component's props on server side.

• branch: Object: Data resolution is done by passing an array of React Router Config's Branches, Objects or Components to resolveInitialData function. branch is the current item of that array. _The branch argument passed to the getInitialData static method_.
• extra?: Object: The extra argument passed to the getInitialData static method or to resolveInitialData.

During SSR, in order to fetch data, the component's static method getInitialData will be called. mapArgsToProps is used to map the arguments passed to that static method into the component's props.

shouldGetData?: (props: Object, nextProps: Object) => boolean (optional)

Function used to check if should get data in the componentWillReceiveProps phase. The purpose of this function is to allow the re fetch of data if the properties passed to the Component have changed. By default, this function always returns false.

It receives two parameters:

• props: Object: The current Component properties.
• nextProps: Object: The next Component properties.

generateComponentKey?: (component: ReactComponent, props: Object) => String (optional)

Server side data and client side data is related by a component key. By default, each Component has an auto incremented key which is generated by the import order (we are assuming that the client and the server will import components in the same order).

There are some cases (1), when we will need to make the key to depend of the component properties.

1: The simplest example is when data fetching depends on React Router's Match. On client side, we will want to re fetch when the url is change, this won't trigger an unmount, but a componentWillReceiveProps.

Injected props and methods

Props

All the mapped properties by the mapDataToProps function.

<WithGetInitialDataComponent />

<WithGetInitialDataComponent /> refers to the components created by the withGetInitialData(options) function.

Props

This section describes the properties that could be passed to the Component.

getInitialData: (key: String) => Object

A function that is used to retrieve the initial data through the component key.

hasLoadedComponent: (key: String) => bool

A function that is used to check if a Component (through it's key) has his data available.

dismissLoadedComponent: (key:String) => null

A function that is used to dismiss a previously loaded data.

A component will dismiss when it's unmounted (or when it's properties have changed and shouldGetData returned true).

Methods

This section describes the methods provided by the Component.

static getInitialData(branch?: Object, extra?: Object) => {key: String, promise: Promise}

This method should be called server side in order to fetch the component data. It will return a Promise which will be resolved when the data has been fetched. The result of the promise is the data fetched (setted by the setData function called in getInitialData).

• branch?: Object: Data resolution is done by passing an array of React Router Config's Branches, Objects or Components to resolveInitialData function. branch is the current item of that array. The branch argument passed to the getInitialData static method.
• extra?: Object: Extra argument that will be used to in order to build the Component's prop. See mapArgsToProps.