React-context-global-state NPM

react-context-global-state

Simple global state for React with Context API

Background

React v16.3 introduces a new Context API. Context API allows to pass values down to a component tree without explicit props.

In favor of writing all components stateless in "thisless" JavaScript, this package is developed. This package provides a simple way to define a global state with Context API.

Install

npm install react-context-global-state

Usage

import React from 'react';
import { createGlobalState } from 'react-context-global-state';

const initialState = { counter: 0 };
const { StateProvider, StateConsumer } = createGlobalState(initialState);

const Counter = () => (
  <StateConsumer name="counter">
    {(value, update) => (
      <div>
        <span>Counter: {value}</span>
        <button onClick={() => update(v => v + 1)}>Click</button>
      </div>
    )}
  </StateConsumer>
);

const App = () => (
  <StateProvider>
    <Counter />
  </StateProvider>
);

Example

The examples folder contains working examples. You can run one of them with

PORT=8080 npm run examples:minimal

and open http://localhost:8080 in your web browser.

You can also try them in codesandbox.io: 01 02 03 04 05

Reference

Syntax

createGlobalState(initialState)

Parameters

initialState: an object like { name1: value1, name2: value2, ... }

Return value

An object of { StateProvider, StateConsumer, setGlobalState }

StateProvider: a component to provide entire state

StateConsumer: a component that receives a required name prop and invokes a child function prop whose signature is (value, update) => {} where value is the state value specified by the name and update is a function to update the value

The update function above is similar to Component.prototype.setState, and accepts either an updating function or a new value itself.

setGlobalState: a function to update a value in global state from outside of components. It recevies a name and a update value (or function).

getGlobalState: a function to get a value in global state from outside of components. It recevies a name.