If you're new to React development, you might have come across a confusion about why you need to bind `this` for methods defined in a React component class but not when using a regular ES6 class. This issue may seem mysterious at first, but once you understand the reasons behind it, you'll see it's actually a design choice that aims to simplify and structure your React code effectively.
In React, the behavior of functions and methods is crucial due to the way it handles the context of `this`. When you define a method in a React component class in the older React versions, you need to bind `this` to the method explicitly in the class constructor or when calling the method. This is because when a method is called in a React component, the context of `this` within that method is not automatically bound to the component instance by default.
On the contrary, when you define a method in a regular ES6 class, the context of `this` within the method is automatically determined by how it is called. This difference in behavior can be confusing for new React developers, and you might wonder why React doesn't automatically handle the binding of `this` like a regular class.
The reason behind this distinct behavior in React is rooted in the concept of JavaScript's function scope and how React components handle re-rendering efficiently. In React, when a method is passed down as a callback or event handler, the binding of `this` that happens explicitly informs React that the method's context is tied to the component it belongs to, ensuring the predictable behavior of the component.
Additionally, manually binding `this` in React components enhances the performance by reducing the number of re-renders triggered by method invocation. When `this` is explicitly bound to the React component instance, React can optimize re-renders more effectively as it knows that the method is associated with a specific component and its state.
Although it may seem like an extra step at first, binding `this` for methods in React components is a fundamental part of React's design philosophy to maintain a clear and predictable component structure. By following this pattern, you ensure that component methods behave consistently and efficiently within the React ecosystem.
In summary, the need to bind `this` for methods defined in React component classes but not in regular ES6 classes is a deliberate choice made by the React team to optimize performance, maintain predictable behavior, and streamline the development process. Understanding this distinction will help you write more robust and efficient React components as you delve deeper into React development.