JavaScript Quiz 2
What is the difference between map() and forEach() methods in JavaScript?
What is the difference between arrow functions and regular functions in JavaScript?
What is the difference between local and global variables in JavaScript?
What is the difference between the spread operator and the rest parameter in JavaScript?
What is the difference between synchronous and asynchronous code in JavaScript?
What is a generator function in JavaScript?
What is the difference between let and const in JavaScript?
What is the difference between a callback function and a promise in JavaScript?
What is the difference between synchronous and asynchronous code in JavaScript?
What is the difference between a class and an object in JavaScript?
What is the difference between map() and forEach() methods in JavaScript?
Both map() and forEach() are used to loop over an array in JavaScript. The main difference between the two is that map() creates a new array with the results of calling a provided function on every element in the original array, while forEach() simply executes a provided function once for each array element.
What is the difference between arrow functions and regular functions in JavaScript?
Arrow functions are a shorthand syntax for writing functions in JavaScript. They have a shorter syntax and do not have their own this keyword, but inherit the this value from the surrounding context. Regular functions have a longer syntax and have their own this keyword, which can be confusing in certain contexts.
What is the difference between local and global variables in JavaScript?
Local variables are declared within a function or block and can only be accessed within that function or block. Global variables, on the other hand, are declared outside of a function or block and can be accessed from anywhere in the code.
What is the difference between the spread operator and the rest parameter in JavaScript?
The spread operator is used to spread an array or object into individual elements, while the rest parameter is used to collect individual elements into an array. The spread operator is denoted by three dots (…), while the rest parameter is denoted by an ellipsis before the parameter name.
What is the difference between synchronous and asynchronous code in JavaScript?
Synchronous code is executed in a single, sequential order, blocking other code from executing until it is complete. Asynchronous code, on the other hand, does not block other code from executing, and can run simultaneously with other code. This is useful for handling long-running operations that would otherwise freeze up your application.
What is a generator function in JavaScript?
A generator function is a special type of function in JavaScript that can be paused and resumed, allowing you to iterate over a sequence of values one at a time. Generator functions use the yield keyword to return a value and pause the function execution, and the next() method to resume execution and retrieve the next value in the sequence.
What is the difference between let and const in JavaScript?
Both let and const are used to declare variables in JavaScript. The main difference between the two is that let variables can be reassigned, while const variables cannot be reassigned. Additionally, const variables must be assigned a value when they are declared, while let variables can be declared without an initial value.
What is the difference between a callback function and a promise in JavaScript?
A callback function is a function that is passed as an argument to another function, and is executed when the first function has completed. A promise is an object that represents the eventual completion (or failure) of an asynchronous operation, and allows you to chain together multiple asynchronous operations in a more readable way. Promises have three states: pending (the initial state), fulfilled (meaning the operation completed successfully), and rejected (meaning the operation failed).
What is the difference between synchronous and asynchronous code in JavaScript?
Synchronous code is executed in a single, sequential order, blocking other code from executing until it is complete. Asynchronous code, on the other hand, does not block other code from executing, and can run simultaneously with other code. This is useful for handling long-running operations that would otherwise freeze up your application.
What is the difference between a class and an object in JavaScript?
A class is a blueprint for creating objects in JavaScript, while an object is an instance of a class. Classes define properties and methods that all objects of that class will have, while objects have their own unique values for those properties. Classes were introduced in ES