Q661. What is babel?
Babel is a JavaScript transpiler to convert ECMAScript 2015+ code into a backwards compatible version of JavaScript in current and older browsers or environments. Some of...
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Q662. Is Node.js completely single threaded?
Node is a single thread, but some of the functions included in the Node.js standard library(e.g, fs module functions) are not single threaded. i.e, Their logic runs outsi...
Q663. What are the common use cases of observables?
An **Observable** (popularized by RxJS and reactive programming) represents a lazy, push-based stream of multiple values emitted over time. Observables excel at handling ...
Q664. What is RxJS?
RxJS (Reactive Extensions for JavaScript) is a library for implementing reactive programming using observables that makes it easier to compose asynchronous or callback-ba...
Q665. What is the difference between Function constructor and function declaration?
The functions which are created with `Function constructor` do not create closures to their creation contexts but they are always created in the global scope. i.e, the fu...
Q666. What is a Short circuit condition?
Short circuit conditions are meant for condensed way of writing simple if statements. Let's demonstrate the scenario using an example. If you would like to login to a por...
Q667. What is the easiest way to resize an array?
The length property of an array is useful to resize or empty an array quickly. Let's apply length property on number array to resize the number of elements from 5 to 2, `...
Q668. What is an observable?
An Observable is basically a function that can return a stream of values either synchronously or asynchronously to an observer over time. The consumer can get the value b...
Q669. Why are inline ref callbacks or functions not recommended?
If the ref callback is defined as an inline function, it will get called twice during updates, first with null and then again with the DOM element. This is because a new ...
Q670. What is the difference between function and class declarations?
The main difference between function declarations and class declarations is `hoisting`. The function declarations are hoisted but not class declarations. **Classes:** ```...