Today we are going to provide basic react js interview question with answer, This quiz series helps to build more understanding on reactjs and java script library for building user interfaces.
1. We can go for keys when there is possibility that our user could change the data.
2. JSX is typesafe.
3. React merges the object you provide into the current state using __________.
4. Arbitrary inputs of components are called __________.
5. _________ can be done while more than one element needs to be returned from a component.
6. Which of the following needs to be updated to achieve dynamic UI updates?
7. Lifecycle methods are mainly used ___________.
8. State can be initialized when code is loaded or state can be set on event changes.
9. ref is used to refer a element / component returned by _______________.
10. In JSX most of the errors can be caught during _________.
11. Components cannot refer to other components in their output.
12. JSX is faster because it performs ____________ while compiling code to JavaScript
13. If our elements are dynamic, react can keep track of the changes using keys.
14. Function that does not change its results for the same set of inputs are called __________.
15. What is the smallest building block of ReactJS?
16. An altered component may be uniquely identified with the help of ref.
17. React considers everything as _______.
18. React keeps track of what items have changed, been added, or been removed from a list using ________.
19. React is mainly for building _____________.
20. React supports all the syntax of _________________.
21. In React state can be accessed using ________.
22. How can we prevent default behavior in React?
23. Invoked once, only on the client, after rendering occurs.
NOTE : we have marked answer in blue color.
Let us know your comment below in comment box.
1. We can go for keys when there is possibility that our user could change the data.
- Keys
- ref
- both
- none of above
2. JSX is typesafe.
- True
- False
3. React merges the object you provide into the current state using __________.
- setState()
- State()
4. Arbitrary inputs of components are called __________.
- Keys
- Props
- Elements
- Ref
5. _________ can be done while more than one element needs to be returned from a component.
- Abstraction
- Packing
- Insulation
- Wrapping
6. Which of the following needs to be updated to achieve dynamic UI updates?
- State
- Props
7. Lifecycle methods are mainly used ___________.
- To keep track of event history
- to enhance components
- freeup resources
- none of the options
8. State can be initialized when code is loaded or state can be set on event changes.
- False
- True
9. ref is used to refer a element / component returned by _______________.
- react()
- render()
- reduce()
- refer()
10. In JSX most of the errors can be caught during _________.
- Interpretation
- Execution
- Compilation
- Build
11. Components cannot refer to other components in their output.
- True
- False
12. JSX is faster because it performs ____________ while compiling code to JavaScript
- Modification
- Compression
- Optimization
- Encryption
13. If our elements are dynamic, react can keep track of the changes using keys.
- True
- False
14. Function that does not change its results for the same set of inputs are called __________.
- Pure functions
- Impure Functions
15. What is the smallest building block of ReactJS?
- none of the options
- props
- elements
- components
16. An altered component may be uniquely identified with the help of ref.
- True
- False
17. React considers everything as _______.
- User interface
- elements
- components
- Objects
18. React keeps track of what items have changed, been added, or been removed from a list using ________.
- state
- props
- keys
- ref
19. React is mainly for building _____________.
- Database
- Connectivity
- User interface
- Design platform
20. React supports all the syntax of _________________.
- ES6
- Redux
- None of options
- Native Java
21. In React state can be accessed using ________.
- current
- state
- current()
- state()
22. How can we prevent default behavior in React?
- None of the options
- using revokeDefault()
- Using preventDefault()
- using avoidDefault()
23. Invoked once, only on the client, after rendering occurs.
- componentWillUnmount
- shouldComponentUpdate
- componentWillMount
- componentDidMount
NOTE : we have marked answer in blue color.
Let us know your comment below in comment box.
Thanks a lot mate!
ReplyDeleteI don't think this answer or question is correct "Lifecycle methods are mainly used freeup resources" because from React docs is talking about componentWillUnmount() not on every lifecycle
ReplyDelete