But the most challenging one is probably a whiteboard interview. In these types of interviews, you have to code in front of a future employer / a senior https://www.globalcloudteam.com/ software developer. It’s not just mastering the technical aspect of JavaScript, it’s about your body language and how you explain your answers.

TypeScript is used by web developers who need a more scalable language for large-scale projects. Companies like Microsoft, Accenture, Slack, AMD, and more currently use TypeScript for many of their projects. If you’re looking for a ‘zero-configuration’ testing experience, Jest might be what you’re looking for. Release by Facebook, Jest focuses on simplicity and works out of the box with no additional setup required.

What is the use of a type of operator?

But once again, it has too many lines of codes as you see below, so it isn’t the ideal version. The new task asks us to obtain only the vegetarian / vegan singers from the passengers’ list by also keeping the first argument in the main question section. We can reach the desired result by using the ‘forEach’ function as well. This solution is even a bit better than the previous one because there is no index expression in this one. Below, [i] represents the current passenger and we simply loop through the ‘passengers’ array to access the names of the passengers.

javascript developer interview questions

The charAt() function of the JavaScript string finds a char element at the supplied index. The index number begins at 0 and continues up to n-1, Here n is the string length. The index value must be positive, higher than, or the same as the string length. Normally, we declare a function and call it, however, anonymous functions may be used to run a function automatically when it is described and will not be called again. Without being requested, a self-invoking expression is automatically invoked (initiated). If a function expression is followed by (), it will execute automatically.

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Arrow functions are an alternative way of defining a JavaScript function. Arrow functions allow you to define a function without using the function() keyword. This syntax means you don’t have to check if a value is defined before you start to use it in a function. Default parameters therefore make a function easier to read and understand. Next, our code checks whether the length of “array_name” is equal to 0.

In JavaScript, null and undefined are two distinct values that represent the absence of a value. Asynchronous code can be used to improve performance by allowing certain tasks to happen concurrently and without blocking the execution of other code. They are defined using square brackets “[]” and elements are separated by commas “,”. Over 3,000 companies and 40% of developers worldwide use HackerRank to hire tech talent and sharpen their skills.

Difference between prototypal and classical inheritance

Functional programming also uses pure functions, meaning functions do not borrow any data outside their scope. If you detect bugs in functional programming, they’ll be much easier to spot and rectify as they’ll be limited to the scope of the respective function. JavaScript still ranks in the top five most wanted programming languages, according to the Stack Overflow Developer Survey 2022. It’s a lightweight language that provides a unified development environment and integrates well with many other frameworks.

javascript developer interview questions

Well, the reason is to test your problem solving skills in general. At times, finding the correct answer may not even be that important. During coding interviews, you are expected to fix coding problems with some theoretical knowledge.

A Day In The Life Of A Node.js Developer

Step 6) Check if the left pointer is less than or equal to a right pointer, then saw the elements in these pointers’ locations. Step 4) Compare the element pointing with the left pointer, and if it is less than the pivot element, then move the left pointer to the right (add 1 to the left index). Continue this until the left side element is greater than or equal to the pivot element. Step 2) Start the left pointer at the first element of the array. DOM stands for Document Object Model and is responsible for how various objects in a document interact with each other.

Its value is a string indicating the data type of the operand. This function takes a node in a binary tree as an argument and performs a depth-first search, printing out the value of each node visited. It first checks if the current node is null, and if so, it returns. Otherwise, it logs the value of the current node to the console. Then, it recursively calls itself on the left and right child nodes of the current node, if they exist.

Junior interview questions

By encapsulating code within a self-invoking function, you can declare variables without the risk of them conflicting with other variables in the global scope. Undeclared variables are those that do not exist in a program and are not declared. If the program tries to read the value of an undeclared variable, then a runtime error is encountered. Undefined variables are those that are declared in the program but have not been given any value.

  • Interviewers would like to know why you answered the way you did, not if you remembered the answer.
  • In this case, the variable `privateVariable` is only accessible within the scope of the self-invoking function and cannot be accessed or modified from outside.
  • Although in the code above, this keyword refers to the object obj2, obj2 does not have the property “address”‘, hence the getAddress function throws an error.
  • As a web developer or a hiring manager for a new development project, you are likely to come across the JavaScript vs TypeScript dilemma.
  • Asynchronous functions, on the other hand, execute each line of code without stopping to wait for a value from a function.
  • Self-invoking functions are commonly used to create a separate scope for variables, functions, or modules, preventing pollution of the global namespace.

Reading a cookie is just as simple as writing one, because the value of the document.cookie object is the cookie. So you can use this string whenever you want to access the cookie. The document is the actual web page being displayed in a browser, while the window object represents an instance of a browser.

The Future of Programming: AI and Interface-Oriented Languages

The code above will clear the existing array by setting its length to 0. This way of emptying the array also updates all the reference variables that point to the original array. Therefore, this method is useful when you want to update all reference variables pointing to arrayList. Above code will set the variable arrayList to a new empty https://www.globalcloudteam.com/how-to-hire-a-javascript-developer/ array. This is recommended if you don’t have references to the original array arrayList anywhere else, because it will actually create a new, empty array. You should be careful with this method of emptying the array, because if you have referenced this array from another variable, then the original reference array will remain unchanged.