React Part 4

Question 1

Controlled components

Answer 1

A component that controls the input elements within the forms on subsequent user input

Question 2

Uncontrolled components

Answer 2

The one that store their own state internally, query dom to find its ref

Question 3

What is Lifting State Up in React?

Answer 3

When several components need to share the same changing data then it is recommended to lift the shared state up to their closest common ancestor

Question 4

Different phases of lifecycles ?

Answer 4

Mounting: The component is ready to mount in the browser DOM
Updating: In this phase, the component gets updated in two ways, sending the new props and updating the state
Unmounting: In this last phase, the component is not needed and gets unmounted from the browser DOM.

Question 5

componentWillReceiveProps

Answer 5

Executed when particular prop updates to trigger state transitions.

Question 6

shouldComponentUpdate:

Answer 6

Determines if the component will be updated or not. (default: true, set to false to prevent a re-render when component receives new prop)

Question 7

ComponentWillUpdate

Answer 7

execute before re-rendering components when state/props changes comfirmed by shouldComponentUpdate return true

Question 8

componentDidUpdate

Answer 8

Mostly it is used to update the DOM in response to prop or state changes.

Question 9

getDerivedStateFromProps

Answer 9

Invoked right before calling render() and is invoked on every render (rarely use)

Question 10

Higher Order Components

Answer 10

A higher-order component (HOC) is a function that takes a component and returns a new component.

Question 11

Stateless Component

Answer 11

If the behaviour is independent of its state then it can be a stateless component

Question 12

What are stateful components?

Answer 12

If the behaviour of a component is dependent on the state of the component then it can be termed as stateful component.

Question 13

React Composition

Answer 13

development pattern built based on React’ original component model where we build components from other components using explicit defined prop or implicit children prop.

Question 14

Why use React Composition ?

Answer 14

This technique prevents us from building too many similar components containing duplicate code and allows us to build fewer components that can be reused anywhere within our application,

Question 15

Specialized Components

Answer 15

A specialized component is a component that is built from its accepted props to handle one specific case.

Question 16

Container Components

Answer 16

A container component, also known as a parent component, is a component that provides the state and behavior to its children components.