
Obviously, this throws an error due to the reason we are trying to access a
`x` property in the `someprop` property which have an `undefined` value. Remember **properties** in an object which does not exist in itself and its **prototype** has a default value of `undefined` and `undefined` has no property x.


Why does this code obj.someprop.x throw an error?

JavaScript's += operator is a handy shorthand for adding a value to a variable and reassigning the result. Learn more about this and how to use it.

What is the JavaScript += Operator and How Do You Use It?

Learn how to use the startsWith() method in JavaScript to check if a string begins with a specified set of characters.

Using the startsWith() Method in JavaScript

Learn how to reverse a string in JavaScript using the split(), reverse(), and join() methods or the reduce() method.

Reverse a String in JavaScript: 2 Easy Methods

Event Target is a property of an event object in JavaScript that refers to the element that triggered the event.

What is event.target in JavaScript?

Discover how to prevent the default behavior of an element and stop event propagation in JavaScript using the preventDefault and stopPropagation.

Difference Between preventDefault and stopPropagation in JavaScript

Learn about the !! operator in JavaScript and its uses for truthy/falsy values, defined/undefined variables, empty arrays and value conversion.

What does the !! operator do in JavaScript?

JavaScript is a multi-paradigm language, supporting imperative/procedural programming along with OOP and functional programming.

Two programming paradigms in JavaScript?

In JavaScript, two objects are considered equal only if they are the same object, not just if they have the same properties and values.