Q2451. How do you prevent promises swallowing errors?
While using asynchronous code, JavaScript’s ES6 promises can make your life a lot easier without having callback pyramids and error handling on every second line. But Pro...
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Q2452. Why do you not need error boundaries for event handlers?
Error boundaries do not catch errors inside event handlers. React doesn’t need error boundaries to recover from errors in event handlers. Unlike the render method and lif...
Q2453. What is deno?
Deno is a simple, modern and secure runtime for JavaScript and TypeScript that uses V8 JavaScript engine and the Rust programming language. It solves the inherent problem...
Q2454. What is the difference between try catch block and error boundaries?
Try catch block works with imperative code whereas error boundaries are meant for declarative code to render on the screen. For example, the try catch block used for belo...
Q2455. How do you make an object iterable in javascript?
By default, plain objects are not iterable. But you can make the object iterable by defining a `Symbol.iterator` property on it. Let's demonstrate this with an example, `...
Q2456. What is the required method to be defined for a class component?
The `render()` method is the only required method in a class component. i.e, All methods other than render method are optional for a class component.
Q2457. What is a Proper Tail Call?
First, we should know about tail call before talking about "Proper Tail Call". A tail call is a subroutine or function call performed as the final action of a calling fun...
Q2458. What are the possible return types of render method?
Below are the list of following types used and return from render method, 1. **React elements:** Elements that instruct React to render a DOM node. It includes html eleme...
Q2459. How do you check an object is a promise or not?
If you don't know if a value is a promise or not, wrapping the value as `Promise.resolve(value)` which returns a promise ```javascript function isPromise(object) { if (Pr...
Q2460. What is the main purpose of constructor?
The constructor is mainly used for two purposes, 1. To initialize local state by assigning object to this.state 2. For binding event handler methods to the instance For e...