React , Redux , Typescript, React Native— Interview Questions


What is DOM ?

Explain Javascript Promises ?

Explain try, catch, throw, finally ?

What are Map, Reduce, Filter ?

What is pure function ?

Difference between Let and Var ?

What is Sync and Async in Javascript ?

What is the Spread Operator ?

What is the difference between Library and Framework ?

What is the difference between === and == ?

What is uni-directional and bi-directional Data flows ?

What are object literals ?

What is Mixins in Javascript ?


What is Typescript ?

What are build in and user defined types ?

What is Class ?

What is interface ?

What is module ?


What is React ?

What is Virtual DOM ?

What is State and Props ?

What are service workers ?

  1. It caches parts of your websites to make load faster.
  2. even if there is a connection lost, user can continue the application in offline.
  3. they enable notifications and pish API’s which are not supported by traditional Web technologies.
  4. They help us for background sync and makes user feel for continuous user experience

What is an HOC or Higher Order Component ?

What is a strict mode ?

Can we use setState in useEffect ?

  1. Don’t use useState with useEffect while fetching data if no dependency is passed, Since it makes the component to fall into infinite loop of setting page state and make the page unresponsive.
  2. when a dependency is passed to useEffect, then there will be no side effects using useState in useEffect.

What is the difference between real DOM and Virtual DOM ?

What are React Hooks ?

Explain each React Hook in brief with example ?

What is Context API in React ?

What is memoization in React ?

What is the difference between Client side rendering and Server side rendering ?

What is Synthetic events ?

What are the phases of React Class components ?

  1. Mounting
  2. Rendering
  3. Updating
  4. Un mounting

Why are keys used in React or React Native ?

React Native

What are hybrid apps ?

What are native apps ?

When will you use ScrollView and Flatlist ?

What is the difference between HOT Reloading and LIVE reloading ?

How to re render a Flat List ?

How does Flexbox differ in mobile hybrid apps and browser ?

What is the engine that react native uses ?

How to use Local storage in Hybrid App ?

What is the use of interaction manager ?

How styling is done in React Native ?


What is Redux ?

  1. Single source of truth
  2. Immutability of state i.e, State is read only
  3. Returning from Pure Functions.

What is Flux ?

What are the principles of Redux ?

  1. Single source of truth.
  2. Immutability of data.
  3. Changes are made in pure functions.

Explain the components of Redux ?

  1. Actions / Action Creators : Action creators simple javascript objects which carries data when dispatched from view to reducer. It has Type and a payload to be passed.
  2. Reducer : Reducer is a Pure Function where it returns the value on the scope of the input values. The values are computed based on previous values or state and a new State is returned. Here mutation is not done to actual state, instead a new state is computed on previous state and returned. These reducers has to be registered in the store.
  3. Store : it is a Simple Javascript Function or Object where it provides Data of application where ever it is necessary. Due to single store concept, it is easy to share data across the application.




Full stack developer, Blogger, Poet, Writer

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Akarsh Saraff

Akarsh Saraff

Full stack developer, Blogger, Poet, Writer

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