Reapex dataloader module

register the module

import { App } from 'reapex'
import dataloader from 'reapex-module-dataloader'

const app = new App()
// 1. register the module
export const { useDataLoader, useLazyDataLoader } = app.use(dataloader)

Use react hooks

const LoaderWithHook = () => {
  const loaderStatus = useDataLoader({
    name: 'api2',
    apiCall: mockApi,
  })

  if (loaderStatus.loading) {
    return <div>loading...</div>
  }
  if (loaderStatus.error) {
    return <div>Error!!!</div>
  }
  return <div>{loaderStatus.data ? loaderStatus.data : 'No Data!'}</div>
}

Lazy load

const LoaderWithHook = () => {
  const [loaderStatus, load] = useLazyDataLoader({
    name: 'api2',
    apiCall: mockApi,
  })

  return <button onClick={() => load()}>click to load</button>
}

API

DataLoaderProps: The parameter of useDataloader hook function

Property	Description	Type	Default	Required
name	The key of the data stored in redux state, has to be unique if dataKey is not provided	string	-	Yes
apiCall	A function that returns promise	(params?: TPramas) => Promise<any>	-	Yes
interval	Fetch data in an interval if given a none 0(ms) number	boolean	0	No
params	The parameters that passed to apiCall function	TParams = any	undefined	No
dataKey	Function that compute a dynamic key based on params	(name: string, params?: TParams) => string	() => 'default'	No
ttl	How much time the cache will valid before making a new data fetching, default 0, no cache. The apiCall function will be called every time	number	0	No
shouldInterval	A function the returns true/false to determine whether the interval function call should continue or not	(data?: TData) => boolean	() => true	No
onSuccess	A function will get called when apiCall run successfully	(data?: TData) => any	-	No
onFailure	A function will get called when apiCall throw an exception	(error?: Error) => any	-	No
dataPersister	An object that configures how to persist the data	DataPersister	-	No
lazyLoad	if dataPersister is configured, it will first use the data from persister then call apiCall to refresh the data	boolean	-	No

useDataLoader() hook

useDataLoader: <TData = any, TParams = any>(props: DataLoaderProps) => [LoaderStatus<TData>, LoadActionCreator]

props: DataLoaderProps

The props: DataLoaderProps are defined in the table above.

LoaderStatus

Property	Description	Type
data	The data that reuturned by apiCall	TData
loading	true when data is loading, otherwise false	boolean
error	An Error object if apiCall threw exception	Error
lastUpdateTime	The timestamp of last time when receiving the data from apiCall	number
lastErrorTime	The timestamp of last time when apiCall threw an exception	number

LoadActionCreator

load: (params?: TParams) => any

A function to call with params which will trigger the apiCall

DataPersister

export interface DataPersister {
  getItem: (key: string, meta?: Meta) => any
  setItem: (key: string, value: any, meta?: Meta) => any
  removeItem: (key: string, meta?: Meta) => any
}

For example, localStorage data persister:

export const LocalStorageDataPersister = (): DataPersister => {
  const getItem = (key: string) => {
    const data = localStorage.getItem(key)
    return data && JSON.parse(data)
  }

  const setItem = (key: string, value: any) => {
    localStorage.setItem(key, JSON.stringify(value))
  }

  const removeItem = (key: string) => {
    localStorage.removeItem(key)
  }

  return {
    getItem,
    setItem,
    removeItem,
  }
}