Quiz for Binding Event Handlers

Q1: Which method is commonly used to bind event handlers in the constructor of a class component?

A. bind() method B. arrow functions C. call() D. apply()

Q2: What is the main issue with not binding event handlers in React class components?

A. Event handlers will execute automatically B. this will be undefined inside the handler C. It will cause memory leaks D. Component will not render

Q3: Which of the following is NOT a valid way to bind event handlers in React?

A. Using bind() in constructor B. Using arrow functions in render() C. Using inline bind() D. Using the static keyword

Q4: Which method results in better performance when binding event handlers in React?

A. Binding in render() B. Binding in constructor C. Using inline bind() D. Using componentDidMount()

Q5: What does using an arrow function in a class property do?

A. Automatically binds this to the class instance B. Creates a static function C. Creates a private method D. Creates a getter

Q6: Which syntax binds the handleClick method in constructor?

A. this.handleClick.bind(this) B. bind(this.handleClick) C. this.bind(handleClick) D. handleClick = this.bind()

Q7: Which binding technique increases the number of functions created on each render?

A. Binding in constructor B. Arrow function in class field C. Binding in render() D. None of the above

Q8: Which ES6 feature helps in avoiding the use of bind in constructor?

A. Destructuring B. Arrow functions C. Spread operator D. Template literals

Q9: Which of the following is true about inline arrow functions in JSX?

A. They do not create new functions B. They are good for performance C. They create a new function on each render D. They are deprecated

Q10: Where should you bind your event handlers for optimal performance?

A. Inside render method B. Inside JSX C. Inside constructor D. Inside componentDidMount()

Q11: How do you define an arrow function as a class property?

A. handleClick = () => {} B. function handleClick() {} C. () => handleClick D. class.handleClick = () => {}

Q12: Which is more concise for defining bound methods?

A. Arrow functions B. bind in constructor C. call() method D. apply() method

Q13: Why is binding in the render() method discouraged?

A. It causes memory leaks B. It is not supported in React C. It creates new function instances on each render D. It doesn’t bind this

Q14: Which is NOT a valid reason to use arrow functions for event handlers?

A. Cleaner syntax B. Avoids rebinding this C. Improves performance D. Prevents rendering

Q15: What problem does this.handleClick = this.handleClick.bind(this) solve?

A. Memory leak B. Incorrect this context C. Undefined method D. Double rendering

Q16: Which function context will be preserved using arrow function?

A. Global context B. Window context C. Component instance context D. Event context

Q17: Which is the best practice in performance-critical apps for event handler binding?

A. Use bind in render B. Use arrow functions in JSX C. Bind once in constructor D. Avoid binding at all

Q18: Which syntax is used in the render method for arrow function event handler?

A. onClick={() => this.handleClick()} B. onClick={this.handleClick()} C. onClick={this.handleClick.bind(this)} D. onClick={handleClick}

Q19: What is a downside of using arrow functions inside render for event handling?

A. They lose this context B. They are slower to run C. They create new functions on each render D. They cause errors

Q20: What happens if you forget to bind an event handler in a class component?

A. React crashes B. The handler runs twice C. this is undefined in the handler D. Component doesn’t mount