When would you want to use Object.create(null) instead of {} to create a new object?

  • When you need an object with no prototype chain to avoid inheriting properties or methods unintentionally.
  • When you want an object that can't be modified or extended further.
  • When you need an object with a predefined set of properties and methods for a specific use case.
  • When you want to create an empty object with the default prototype chain.
Object.create(null) is used when you need an object with no prototype chain (a "null prototype"), which means it won't inherit any properties or methods from Object.prototype. This can be useful for creating objects where you want complete control over the properties and avoid unintentional inheritance.

Which of the following is a method to create an object in JavaScript?

  • Object.create()
  • new Object()
  • createObject()
  • initializeObject()
In JavaScript, you can create an object using the Object.create() method. This method allows you to specify the prototype object from which the new object should inherit properties and methods. The new Object() syntax is less commonly used for object creation.

What does AJAX stand for in web development?

  • Asynchronous JavaScript and XML
  • Advanced JavaScript and XML
  • Asynchronous JavaScript and XHTML
  • Advanced JavaScript and HTML
AJAX stands for "Asynchronous JavaScript and XML." It is a set of web development techniques used to create asynchronous web applications. While XML was commonly used in the past, JSON is more prevalent today for data interchange in AJAX requests.

How can you add a new property to a JavaScript object

  • a) By using the Object.assign() method.
  • b) By using the Object.addProperty() method.
  • c) By simply assigning a value to a new property name.
  • d) By using the addProperty() function.
You can add a new property to a JavaScript object by simply assigning a value to a new property name. For example, myObject.newProperty = 'some value';. While you can use methods like Object.assign() to copy properties from one object to another, it's not used for adding new properties. There's no Object.addProperty() or addProperty() method.

A _______ is a self-contained block of code that manipulates data, and can be thought of as an object in object-oriented programming.

  • Function
  • Module
  • Class
  • Closure
A Module is a self-contained block of code in JavaScript that manipulates data and can be thought of as an object in object-oriented programming. Modules help encapsulate functionality and data, providing a clean and organized code structure.

In JavaScript, the _________ property is a reference to an object from which the current object inherits properties.

  • prototype
  • this
  • parent
  • child
In JavaScript, the prototype property is a reference to an object from which the current object inherits properties and methods. When you access a property or method on an object, JavaScript first looks for it on the object itself and then, if not found, on its prototype. Understanding prototypal inheritance is crucial in JavaScript.

The _______ method returns the removed item when an element is removed from an array.

  • shift()
  • pop()
  • remove()
  • splice()
The pop() method in JavaScript removes the last element from an array and returns that removed element. It's useful when you need to remove and capture the last item in an array. For instance, let removed = myArray.pop() would remove the last element from myArray and store it in the removed variable.

The concept of closures and lexical scoping in JavaScript is based on the ________ principle.

  • Scope
  • Encapsulation
  • Abstraction
  • Inheritance
The concept of closures and lexical scoping in JavaScript is based on the "Scope" principle. In JavaScript, scope determines the accessibility of variables and functions in different parts of your code, and closures are a powerful feature that leverages lexical scope to maintain access to variables even after their containing functions have finished executing.

How does the "this" keyword behave in arrow functions inside methods?

  • It refers to the instance of the class containing the method.
  • It refers to the global object (e.g., window in the browser).
  • It throws an error since arrow functions cannot be used inside methods.
  • It refers to the parent function's "this" value.
In arrow functions inside methods, the "this" keyword retains the value of the outer scope, typically the class instance. This behavior is different from regular functions, which have their own "this" binding. Understanding this behavior is crucial in object-oriented JavaScript programming.

What is the purpose of the "else" statement in JavaScript?

  • To specify an alternate code block to execute when the condition is false
  • To terminate the program
  • To define a variable
  • To loop through an array
The "else" statement in JavaScript serves the purpose of specifying an alternate code block to execute when the condition specified in the "if" statement is false. It provides an alternative path for your code's execution.