Q791. What are the differences between promises and observables?
Some of the major difference in a tabular form | Promises | Observables | | ------------------------------------------------------------------ | -------------------------...
Technical Question Bank · Peer-Reviewed
Job Interview Questions and Answers Directory
Search and filter frequently asked interview questions across technical, programming, and behavioral domains. Tailor your interview preparation by difficulty for freshers or experienced developers (1,100 available).
Active:
Tag: javascript ×
Q792. How to use https instead of http in create-react-app?
You just need to use `HTTPS=true` configuration. You can edit your `package.json` scripts section: ```json "scripts": { "start": "set HTTPS=true && react-scripts start" }...
Q793. What is heap?
Heap(Or memory heap) is the memory location where objects are stored when we define variables. i.e, This is the place where all the memory allocations and de-allocation t...
Q794. How to avoid using relative path imports in create-react-app?
Create a file called `.env` in the project root and write the import path: ``` NODE_PATH=src/app ``` After that restart the development server. Now you should be able to ...
Q795. What is an event table?
Event Table is a data structure that stores and keeps track of all the events which will be executed asynchronously like after some time interval or after the resolution ...
Q796. How to update a component every second?
You need to use `setInterval()` to trigger the change, but you also need to clear the timer when the component unmounts to prevent errors and memory leaks. ```javascript ...
Q797. What is a microTask queue?
Microtask Queue is the new queue where all the tasks initiated by promise objects get processed before the callback queue. The microtasks queue are processed before the n...
Q798. Why is a component constructor called only once?
React's _reconciliation_ algorithm assumes that without any information to the contrary, if a custom component appears in the same place on subsequent renders, it's the s...
Q799. What is the difference between shim and polyfill?
A shim is a library that brings a new API to an older environment, using only the means of that environment. It isn't necessarily restricted to a web application. For exa...
Q800. How to define constants in React?
You can use ES7 `static` field to define constant. ```javascript class MyComponent extends React.Component { static DEFAULT_PAGINATION = 10; } ```