Working with objects in a JavaScript Arrow Function

The JavaScript Arrow function is a shorter way of writing a function expression. Let us say you have a function expression as below, var add = function(num1,num2){ return num1+num2; } The above function can refactor for a shorter syntax using the arrow function as below, var add = (num1,num2) => num1+num2; So, as you see, … Continue reading Working with objects in a JavaScript Arrow Function

How to use for…of loop with an Object in JavaScript

In my last post, I discussed Always Use the for…of loop to iterate in JavaScript. After this post, I got a question that, is it possible to use for…of loop with an object? Means, can you use the for…of loop to iterates properties of an object.  Let us try this, let Product = { Id: … Continue reading How to use for…of loop with an Object in JavaScript

A JavaScript function inside a Block Scope: Simplified

Scoping determines the visibility of a variable, an object, or a function.  For example, a variable defined inside a function is visible or can be accessed only inside that particular function.   JavaScript has 4 types of scope.  Global scopeFunctional scopeLexical ScopeBlock Scope Out of the above four scoping, Block Scoping became part of JavaScript … Continue reading A JavaScript function inside a Block Scope: Simplified

How to manually pass the value of ‘this’ object in a JavaScript function

Every JavaScript function has a ‘this’ object, and the value of ‘this’ object depends on the way you call the function. To pass the value of ‘this’ manually, you need to call the function indirectly. In JavaScript, you call a function indirectly to pass the value of ‘this’ object manually. Manually calling a function is … Continue reading How to manually pass the value of ‘this’ object in a JavaScript function

How to make a property non-enumerable in JavaScript?

By default, all the properties of JavaScript objects are enumerable. That means you can enumerate them in a for loop or read them using the Object.values(). Let us consider an object Dog as shown below, let Dog = { name :'foo', age: 9, canRun : true, eatMilk : false } You can enumerate all properties … Continue reading How to make a property non-enumerable in JavaScript?

How to merge arrays using spread operator in JavaScript?

Have you come across a requirement to merge two or more arrays  into another array? Let us say, you have two arrays as shown below, const metrocities = ['Delhi', 'Mumbai','Chennai','Bangalore','Hyderabad']; const smallcities = ['Jamshedpur','Pune','Lucknow','Trivandrum']; You need to merge them in another array with optional extra elements in the resultant array. JavaScript array spread operator makes … Continue reading How to merge arrays using spread operator in JavaScript?

How to create Private Properties in JavaScript.

We don't have Access Modifiers in JavaScript, and all properties of an object are public, which means you can read and modify them outside the object. But what if you have a requirement to create private properties?  Consider Product object as mentioned below, let Product = { id: '1', price: 200, title: 'Pencil' } console.log(Product.id); … Continue reading How to create Private Properties in JavaScript.

Explain Object.keys in JavaScript

Enumerating through the properties of a JavaScript object is a persistent requirement. Hence it becomes a popular question in a JavaScript interview. Any good JavaScript developer must know about various available options. Note: You can find a video tutorial on the same at the end of the article. To start with considering the Dog object … Continue reading Explain Object.keys in JavaScript