Introduction Function declarations and expressions
🔍 Dive into the heart of JavaScript, where functions and methods reign supreme. This quiz is designed for everyone passionate about coding – from those taking their first steps in JavaScript to seasoned developers looking to brush up on their knowledge. 🌟
Here’s a sneak peek of what’s in store:
- Do you know the ins and outs of function declarations and expressions?
- Can you navigate the nuances of arrow functions?
- Are you adept at understanding how ‘this’ keyword works in different contexts?
🌈 No coding required in this quiz – just your sharp mind and enthusiasm. It’s a great opportunity to assess your understanding and maybe even learn something new along the way! 🧠
JavaScript Functions and Methods
JavaScript functions and methods are essential for organizing and reusing code. Functions allow you to define a block of code, call it, and execute it as many times as needed. Methods are functions that belong to an object.
1. Function Declaration
Example: Declaring a simple function
function greet(name) {
return `Hello, ${name}!`;
}
console.log(greet(‘Alice’)); // Output: “Hello, Alice!”
Explanation: This is a basic function declaration where greet is a function that takes one parameter, name, and returns a greeting message.
2. Function Expression
Example: Creating a function expression
const square = function(number) {
return number * number;
};
console.log(square(4)); // Output: 16
Explanation: A function expression assigns an anonymous function to a variable (square). This function can then be called using the variable name.
3. Arrow Functions
Example: Using an arrow function
const add = (a, b) => a + b;
console.log(add(2, 3)); // Output: 5
Explanation: Arrow functions provide a more concise syntax for writing functions. They are particularly useful for short functions and when using higher-order functions.
4. Methods in Objects
Example: Method in an object
const person = {
name: ‘Alice’,
greet: function() {
return `Hello, I’m ${this.name}`;
}
};
console.log(person.greet()); // Output: “Hello, I’m Alice”
Explanation: Methods are functions that are stored as object properties. In this example, greet is a method of the person object.
Quiz Questions and Answers
Q1: What is the difference between a function declaration and a function expression in JavaScript?
- A) Only a function declaration can have a name
- B) A function declaration is hoisted, but a function expression is not
- C) Function expressions cannot take parameters
Answer: B) A function declaration is hoisted, but a function expression is not
Q2: What is the primary use of arrow functions in JavaScript?
- A) To create methods in objects
- B) For shorter syntax and handling this differently
- C) To declare global functions
Answer: B) For shorter syntax and handling this differently
Q3: How do you call a function stored in a variable myFunc?
- A) myFunc;
- B) call myFunc;
- C) myFunc();
Answer: C) myFunc();
Q4: What will be the output of the following code?
function multiply(a, b) {
return a * b;
}
console.log(multiply(2, 3));
- A) 6
- B) “2 * 3”
- C) undefined
Answer: A) 6
Q5: In the context of a method, what does the keyword this refer to?
- A) The global object
- B) The function itself
- C) The object that the method is a part of
Answer: C) The object that the method is a part of
These examples and questions highlight the importance of understanding JavaScript functions and methods, crucial for organizing code and creating efficient, reusable scripts.