Google JavaScript Interview Questions You Should Prepare in 2023

In the world of technology, Google is considered one of the giants, known for its innovative products and advanced technologies. I work at Google. The application process at Google is known to be demanding and rigorous, especially for technical positions.If you’re preparing for a JavaScript interview at Google, you should be prepared to put your broad language skills to the test, with their intricacies and practical applications.JavaScript you should prepare for when applying for a job at Google.

1. Closures and Scope

Closing is a fundamental concept in JavaScript. They are created whenever a function is defined inside another function and has access to the variables of its outer function. Understanding closures is essential to addressing scoping and memory management issues.

Question: Explain what a closure is and give an example.

function outerFunction() {
  const outerVariable = "I am from the outer function.";

  function innerFunction() {
    console.log(outerVariable);
  }

  return innerFunction;
}

const closureExample = outerFunction();
closureExample(); // Output: "I am from the outer function."

2. Promises and Async/Await

Asynchronous programming is a fundamental aspect of modern web development, and Google interviews are often about promises and asynchrony/expectations.

Question: Compare Promises and Async/Await in JavaScript and give an example of each.

// Using Promises
function fetchDataWithPromise() {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      resolve("Data fetched successfully!");
    }, 1000);
  });
}

fetchDataWithPromise()
  .then(data => console.log(data))
  .catch(error => console.error(error));

// Using Async/Await
async function fetchDataWithAsync() {
  try {
    const data = await fetchDataWithPromise();
    console.log(data);
  } catch (error) {
    console.error(error);
  }
}

fetchDataWithAsync();

3. Object-Oriented JavaScript

Google interviews often deepen your understanding of Object Oriented Programming (OOP) principles in JavaScript.

Question: Explain Explain the concept of prototype inheritance in JavaScript and provide an example.

function Animal(name) {
  this.name = name;
}

Animal.prototype.makeSound = function() {
  console.log("Some generic animal sound");
};

function Dog(name, breed) {
  Animal.call(this, name);
  this.breed = breed;
}

Dog.prototype = Object.create(Animal.prototype);
Dog.prototype.constructor = Dog;
Dog.prototype.makeSound = function() {
  console.log("Woof!");
};

const myDog = new Dog("Buddy", "Golden Retriever");
myDog.makeSound(); // Output: "Woof!"

4. JavaScript’s this Keyword

Understanding the behavior of this keyword is essential for working with objects, classes, and function contexts.

Question: Explain how the keyword This keyword works in JavaScript and provides examples of its behavior.

// Global context
console.log(this === window); // Output: true

function myFunction() {
  console.log(this === window);
}

myFunction(); // Output: true

const myObject = {
  property: "I belong to myObject",
  printProperty: function() {
    console.log(this.property);
  }
};

myObject.printProperty(); // Output: "I belong to myObject"

5. ES6 Features

ECMAScript 6 (ES6) introduced several important features in JavaScript that are commonly used in modern development.

Question: Why discuss the features introduced in ES6 and provide examples of at least two of them.

// Arrow Functions
const add = (a, b) => a + b;

// Destructuring
const person = { name: "Alice", age: 30 };
const { name, age } = person;

console.log(name); // Output: "Alice"
console.log(age); // Output: 30

Getting a job at Google requires a solid understanding of JavaScript, its basic concepts and practical applications. These interview questions are just a starting point, and you should be prepared to delve into JavaScript as you prepare. Google interviews are known for their depth and breadth. So make sure you study well, practice coding and familiarize yourself with the intricacies of the language.

Good luck on your journey to the Google JavaScript Interview!

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