What is Imperative programming in React?

React is a popular JavaScript library for building user interfaces and web applications. It is based on declarative programming, which allows developers to describe what they want to achieve, and React takes care of managing the underlying DOM updates. However, there are instances where Imperative programming in React becomes necessary to perform specific tasks or interact with the DOM directly.

If you want to learn about declarative programming, read this.

Imperative programming in React

Imperative programming involves giving step-by-step instructions to achieve a specific outcome by interacting with the DOMThe Document Object Model (DOM) is a programming interface for HTML and XML documents that represents the structure of the document as objects, allowing programs to interact with and manipulate the content and structure of web pages. directly through code. While it's generally recommended to follow a declarative approach in React, understanding Imperative programming can be valuable for handling unique scenarios and optimizing certain tasks.

When to use Imperative programming in React?

Imperative programming should not be used for normal purposes in React, as it can make the code more complex and harder to maintain. Declarative programming is generally preferred because it hides the low-level details of DOM manipulation and state management, leading to more concise and readable code, which can be easily understood by everyone.

However, there are some situations where Imperative programming might be necessary or beneficial:

Direct DOM manipulation

React abstracts DOM manipulation through the virtual DOM, but there might be cases where direct DOM manipulation is required, such as integrating with third-party libraries or accessing elements that are not easily accessible through React components.

Animations

For complex animations or performance-intensive tasks, using imperative approaches can sometimes lead to more efficient and smooth animations.

Integrating with non-React code

When integrating React with legacy code or third-party libraries, Imperative programming may be necessary to interface with codebases that don't follow React's declarative paradigm.

Code example

Let's look at a code example where Imperative programming can be used to render our web application and manipulate the DOM directly.

Code explanation

1. Lines 4–13: We define the handleButtonClick function, which will be called when the "Retrieve Value" button is clicked. Inside this function, we use the document.getElementById('inputField').value to imperatively retrieve the value from the input field with the ID "inputField".

2. Lines 9–13: We use the document.getElementById('outputLabel') to retrieve the label element with the ID "outputLabel" and store it in the labelElement variable. We then update the textContent of the labelElement with the retrieved input value (inputValue).

3. Lines 16–23: In the JSX part of the component, we render an h1 heading, an input element with the id "inputField", a "Retrieve Value" button, and a p element containing a span with the id "outputLabel". The retrieved value will be displayed within this span element.

Reference to Imperative programming

Imperative programming is a programming paradigm where the focus is on providing explicit, step-by-step instructions to the computer on how to achieve a specific task. In this example, when the "Retrieve Value" button is clicked, the Imperative programming approach is used to directly manipulate the DOM to retrieve the value entered in the input field and set it as the content of a label element.

Instead of relying on React's state and hooks, the code uses standard JavaScript and DOM manipulation methods like the document.getElementById('inputField').value to fetch the input field's value and update the label element's textContent. This direct and explicit manipulation of the DOM elements bypasses React's virtual DOM and state management, and provides fine-grained control over the specific task of retrieving and displaying the input value.

Conclusion

Imperative programming in React is generally avoided in favor of a declarative approach to managing the user interface efficiently. However, there are scenarios where Imperative programming can be beneficial, such as direct DOM manipulation, complex animations, and integrating with non-React codebases.