MobxCache

An observable data cache with MobX.

Installation

If using npm to manage your dependencies, you can easily do:

npm install --save mobx-cache

Also, make sure mobx is installed since this library relies on it.

Example 1: Simple hello world

import React from "react"
import MobxCache from "mobx-cache"
import { observer } from "mobx-react"
 
var helloMessages = new MobxCache((name) => `Hello, ${name}`)
 
const HelloWorldApp = observer(function HelloWorldApp(props) {
  return (
    <div>
      <h1>{helloMessages.get(props.name).value}</h1>
    </div>
  )
})
 
React.render(<HelloWorldApp name="John Doe" />, document.body)
 
// The next line will update the cache and cause `HelloWorldApp` to re-render
// with the new message:
helloMessages.populate('John Doe', 'Hello again, John!')

The above example is for demonstration purposes only. It may not be useful in real life. This library is especially useful when used for data fetching as the next example shows.

Example 2: User profile

import React from "react"
import MobxCache from "mobx-cache"
import { observer } from "mobx-react"
 
var usersCache = new MobxCache((id) => fetch(`/users/${id}`))
 
const UserProfile = observer(function HelloWorldApp(props) {
  const entry = usersCache.get(props.id)
  if (entry.status !== 'success') {
    return <div>Loading...</div>
  }
 
  const user = entry.value
  return (
    <div>
      <img src={user.image} />
      <h1>{user.name}</h1>
      <p>{user.bio}</p>
    </div>
  )
})
 
// Rendering with the id 199 will cause the fetching of user 199.
React.render(<UserProfile id={199} />, document.body)
 
// When we render with a different id, the new user will be fetched and rendered.
React.render(<UserProfile id={299} />, document.body)

The fetch function can be any function that sends a request to the given url and returns a promise. The promise will automatically be handlded by MobxCache.