How to send the current component’s state to an external function

React is a very famous and powerful library for building user interfaces in website development. Passing data from one component to another is crucial to developing dynamic websites. One such scenario is passing the state of a component to an external methodAn external method refers to a function or procedure that is defined outside the current code scope, often in a separate file or module, and is invoked or utilized by other components or modules. or function.

This Answer will explore how to pass a component’s state as a parameter to an external method or function in React.

Understanding the core concept

At its core, the main concept is to encapsulate a component’s state and pass it as a parameter to an external method when the need arises. This technique allows us to develop highly dynamic websites while writing clean, efficient code.

Let’s break down the process step by step.

Creating a stateful component

Firstly, we need to create a stateful component to manage the state. For instance, consider the code below:

import React, { useState } from 'react';
import externalMethod from './ExternalMethod';
import './Counter.css';
const Counter = () => {
const [count, setCount] = useState(0);
const handleClick = () => {
externalMethod(count);
};
return(
<div className="counter-container">
<h1>Counter: {count}</h1>
<button onClick={() => setCount(count + 1)}>Increment</button>
<button onClick={handleClick}>Send State to External Method</button>
</div>
);
};
export default Counter;

Explanation

  • Line 2: Here we are importing externalMethod from an external file named as ExternalMethod.

  • Line 6: The useState hook is used to declare state variable count and setCount function to change the value of the state variable count. Initial value of count variable is set to 0.

  • Line 8: The handleClick function is defined, which triggers the externalMethod function inside it and passes state variable count as a parameter to external function.

  • Line 12: The return statement simply renders JSX elements, which include:

    • <h1> that shows the current value of the count variable.

    • <button> that triggers the setCount function upon clicking it, which increments the value of the count variable.

    • Another <button> element that calls handleClick function, which, in return, calls externalMethod function, and it logs the current value of the count variable.

Creating externalMethod

In an external file named as ExternalMethod.js, we are creating our external method that will take data passed to it from the stateful component and log it to the console.

const externalMethod = (data) => {
console.log(`Received value from Counter component: ${data}`);
};
export default externalMethod;
externalMethod

In the end, we are just exporting this externalMethod to be imported by other components.

Integrating our created component

Now, the next step is to integrate our custom component into our main component App.js.

import Counter from './Counter';
import './App.css';
function App() {
return (
<div className="app-container">
<h2>React Counter App</h2>
<Counter />
</div>
);
}
export default App;

Explanation

In this main App.js component, we’ll import our created stateful component and render it inside the return statement.

Code in action

Run the code below and navigate to the provided link:

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <link rel="icon" href="%PUBLIC_URL%/favicon.ico" />
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <meta name="theme-color" content="#000000" />
    <meta
      name="description"
      content="Web site created using create-react-app"
    />
    <!--<link rel="apple-touch-icon" href="%PUBLIC_URL%/logo192.png" />
      manifest.json provides metadata used when your web app is installed on a
      user's mobile device or desktop. See https://developers.google.com/web/fundamentals/web-app-manifest/
    -->
    <link rel="manifest" href="%PUBLIC_URL%/manifest.json" />
    <!--
      Notice the use of %PUBLIC_URL% in the tags above.
      It will be replaced with the URL of the `public` folder during the build.
      Only files inside the `public` folder can be referenced from the HTML.

      Unlike "/favicon.ico" or "favicon.ico", "%PUBLIC_URL%/favicon.ico" will
      work correctly both with client-side routing and a non-root public URL.
      Learn how to configure a non-root public URL by running `npm run build`.
    -->
    <title>React App</title>
  </head>
  <body>
    <noscript>You need to enable JavaScript to run this app.</noscript>
    <div id="root"></div>
    <!--
      This HTML file is a template.
      If you open it directly in the browser, you will see an empty page.

      You can add webfonts, meta tags, or analytics to this file.
      The build step will place the bundled scripts into the <body> tag.

      To begin the development, run `npm start` or `yarn start`.
      To create a production bundle, use `npm run build` or `yarn build`.
    -->
  </body>
</html>
Code in action

Conclusion

Passing the component’s state effectively to the external method is an important concept in React development. This approach enhances maintainability and modularity and ensures seamless communication between different components. Developers can create easily maintainable, robust, and efficient React applications by employing state encapsulation inside a component and using well-defined methods to transmit it externally.

Free Resources

Copyright ©2025 Educative, Inc. All rights reserved