In Javascript, date and time are handled with the built-in Date object. The Date objects has several methods such as getDate(), getMonth(), toLocaleString() etc to customize the format of the date-time string.

Tagged templates can be thought of as an advanced form of template literals, where the placeholders (${variable}) and text are passed through a function.

Pre-loading an image is a popular technique to improve performance. However it is also possible to pre-decode the image for a bigger performance boost.

ES6 Template Literals is the new way of creating multi-line strings in Javascript. Variables and expressions can also be substituted in a template literal multi-line string.

Sometimes it is required to keep repeating a string for a specific number of times. The new ES6 function repeat() can help you to do so.

It is sometimes required to make sure that strings are of a specific length. padStart() and padEnd() functions can help you to achieve this.

Strings can be trimmed in Javascript using the native trim functions — trim(), trimStart() & trimEnd()

The Intersection Observer API is probably one of the most useful Web APIs that have been released recently. The API keeps track of intersection between two elements in a webpage.

ES6 has brought forwards newer ways of checking for substrings. The best part is that they all return either a true or false — unlike the usual indexOf() method.

Previously finding whether an element has entered the screen used to be a pain, but the new Intersection Observer API makes this quite easy, and less error prone.

JSON.parse accepts an optional second parameter - the reviver function. The purpose of this function is to modify the result before returning, and can be thought of as filter function.

360-degree photos and videos really give an enhanced user experience. They can be embedded in web pages using Google VR Javascript SDK.

The new <dialog> tag makes it easier to create dialogs and lightboxes. With Javascript you can also call methods to open the dialog or close it, or know when the dialog was closed.

Creating an element which would become fixed during scrolling has become very easy with CSS position : sticky. And with the new Intersection Observer API, it can be detected when an element comes in/out of sticky position.

Changing screen orientation becomes somewhat necessary in some cases, like playing HTML5 games in the browser. Screen orientation can be changed and locked using the new Screen Orientation API.

Modern browsers have brought forward the unhandledrejection event. This is fired when a Promise is rejected, but there is no rejection handler function implemented in the code.

Loading external CSS files with Javascript is beneficial because it improves the loading time of the page.

Loading Javascript files dynamically is beneficial because it improves the loading time of the page. It can be done by appending a new script tag in the html.

With a lot of stress on "offline mode for web applications", applications need to know when the user has gone offline. They also need to know when the user comes back online again.

In modern browsers text to speech feature is built natively in them. This means that you don't need external plugins or APIs to convert text to speech !