Why Should You Avoid Using Bind and Inline Arrow Functions in React's Render Method?

Bind and Inline Arrow Functions in Render Method: Consequences and Alternatives

Introduction:

In React, rendering performance can be impacted if method binding or inline arrow functions are used within the render method. This is because it can trigger the creation of new methods instead of reusing existing ones, resulting in potential performance loss.

Avoiding Bindings in Render Methods:

To avoid binding issues in the render method, there are a few approaches:

• Binding in the Constructor: Methods can be bound in the constructor using this.methodName = this.methodName.bind(this);.
• Property Initializer Syntax: Properties can be initialized as arrow functions directly within the class, as in: methodName = () => {...}.

Addressing Parameters Passing in Bindings:

When it comes to passing extra parameters within bindings, there are alternative approaches to avoid inline arrow functions in the render method:

• Creating a Custom Component: Component-specific logic can be wrapped in a separate child component, passing necessary props and handling the onClick event within it.
• Using Arrow Functions in the Outer Scope: Arrow functions can be defined outside the render method, passing the extra parameters as arguments to those functions.

Code Sample:

Here's an example of implementing the alternative approaches mentioned above:

class MyComponent extends React.Component {
  constructor(props) {
    super(props);
    this.handleClick = this.handleClick.bind(this);
  }

  // Binding in constructor
  handleClick() {
    console.log("Constructor binding");
  }

  // Property initializer syntax
  deleteTodo = () => {
    console.log("Property initializer binding");
  };

  handleClickWithArgs = (el) => {
    console.log(`Delete todo: ${el}`);
  };

  render() {
    // Arrow function in constructor (no extra parameters)
    return (
      <div onClick={this.handleClick}>
        {" "}
        Click Me Constructor Binding{" "}
      </div>
    );
  }
}

function App() {
  const todos = ["a", "b", "c"];

  // Using arrow functions in the outer scope
  const handleDeleteTodo = (el) => {
    console.log(`Delete todo: ${el}`);
  };

  return (
    <div>
      {todos.map((el) => (
        <MyComponent key={el} onClick={handleDeleteTodo} />
      ))}
    </div>
  );
}

ReactDOM.render(<App />, document.getElementById("root"));

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