How to create global variable in react js?

November 25, 2024

Hi Friends 👋,

Welcome To aHoisting!

To create global variable in react js, you can use createContext, useContext to manage global variable in react js.

Today, I am going to show you, how to create global variable in react js.

Table of contents

Install and create a new React app.
Import react component.
Create a Component.

Let’s start with the first step.

Step 1: Install and create a new React app.

First you have to install the React project. You should use create-react-app command to create a new React project.

npx create-react-app my-app
cd my-app
npm start

Step 2: Import react component.

After installing, you have to import your React component.

import React, { createContext, useContext, useState } from "react";

Step 3: Create a Component.

You can use onClick={() => setGlobalVariable("New Value!") to create global variable in react js.

<div>
  <p>Global Variable: {globalVariable}</p>
      <button onClick={() => setGlobalVariable("New Value!")}>
        Update Global Variable
      </button>
</div>

Create global variable example.

The below code is an example of a React. You have to import react and set createContext, useContext to create global variable in react js.

App.js

import React, { createContext, useContext, useState } from "react";

// Create a Context
const GlobalContext = createContext();

// Create a Provider Component
export const GlobalProvider = ({ children }) => {
  const [globalVariable, setGlobalVariable] = useState("Hello, World!");

  return (
    <GlobalContext.Provider value={{ globalVariable, setGlobalVariable }}>
      {children}
    </GlobalContext.Provider>
  );
};

// Hook to use the Global Variable
export const useGlobal = () => useContext(GlobalContext);

// App Component
const App = () => {
  return (
    <GlobalProvider>
      <ComponentA />
    </GlobalProvider>
  );
};

// Example Component
const ComponentA = () => {
  const { globalVariable, setGlobalVariable } = useGlobal();

  return (
    <div>
      <p>Global Variable: {globalVariable}</p>
      <button onClick={() => setGlobalVariable("New Value!")}>
        Update Global Variable
      </button>
    </div>
  );
};

export default App;

In the above code example, I have used the createContext`, `useContext to create global variable in react js.

Check the output of the above code.

All the best 👍