react-lightning-context

A super performant lightning fast context library that only re-renders what has changed and nothing else. This library is a drop in replacement of the official React Context.

Why ?

When building web apps at scale one of the main problems is performance over time. When you have 20+ multiple teams contributing to a same code base it is impossible to not hit this bottleneck. This library tries to mitigate some of this problem by providing a Context API that is reliant ant performant. It tries to avoid the un-necessary re-renders problem that the React Context has by only re-rendering what is upmost needed. As a result performance can be boosted dramatically.

This is NOT a state management library. Just a performant React Context replacement. You can also mix this up with redux for example and get a full redux experience but this is outside the scope of this library.

Libraries comparison

The bordered area is where the element is re-rendered. In the examples, the button is updating only one of the properties in the internal Context value.

Using react-lightning-context	Using React Context

As you can see react-lightning-context only re-renders what has only changed vs React Context that re-renders everything within the Provider

How to install

  yarn add react-lightning-context

API Documentation

You can check the full library documentation here!!!!.

How to use it with an easy example

The main idea ia following the same patterns and api that React Context provides with a little twist. This is doing the same as the previous example but with hooks.

  import { createContext, useContext } from 'react-lightning-context';
  const defaultValue = { valueA: { a: { b: 222, r: 333 } }, valueB: 222, valueC: 444 };
  const Context = createContext(defaultValue);

  const UseLightningContextHookComponent = () => {
    const { valueC } = useContext({ slices: ['valueC'] }, Context);
    return <label>{valueC}</label>;
  };

  const ExampleA = () => (
    <Context.Provider>
      <UseLightningContextHookComponent />
    </Context.Provider>);
};

What is going on here?

• createContext is creating the context.
• Context.Provider is defining the area in which the context data is going to be shared.
• useContext will listen to changes in the Context value and will be updated ONLY when the values on the slices prop in the context has changed. You can listen to more than one field, or you can go deep down into the props. ex: valueA.a.r.

Try it