Quiz Progress: React

1/20
React is mainly for building ___
- Database
- Connectivity
- User interface
- Design Platform
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2/20
Lifecycle methods are mainly used ___
- to keep track of event history
- to enhance components
- freeup resources
- none of the options
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3/20
____ can be done while more than one element needs to be returned from a component.
- Abstraction
- Packing
- Insulation
- Wrapping
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4/20
How do you access a function fetch() from a h1 element in JSX?
- <h1>{fetch()}</h1>
- <h1>${fetch()}</h1>
- <h1>{fetch}</h1>
- <h1>${fetch}</h1>
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5/20
Which method in a React Component should you override to stop the component from updating?
- willComponentUpdate
- shouldComponentUpdate
- componentDidUpdate
- componentDidMount
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6/20
What's used to pass data to a component from outside?
- setState
- render with arguments
- PropTypes
- props
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7/20
Which method in a React Component is called after the component is rendered for the first time?
- componentDidUpdate
- componentDidMount
- componentMounted
- componentUpdated
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8/20
Which of the following is correct syntax for a button click event handler, foo?
- <button onclick={this.foo()}>
- <button onclick={this.foo}>
- <button onClick={this.foo()}>
- <button onClick={this.foo}>
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9/20
What happens when you call setState() inside render() method?
- Repetitive output appears on the screen
- Duplicate key error
- Stack overflow error
- Nothing happens
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10/20
What happens when the following render() method executes?
render(){
let langs = ["Ruby","ES6","Scala"]
return (<div>
{langs.map(it => <p>{it}</p>)}
</div>)
}
- Displays the list of languages in the array
- Error. Cannot use direct JavaScript code in JSX
- Displays nothing
- Error. Should be replaced with a for..loop for correct output
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11/20
How do you write an inline style specifying the font-size:12px and color:red; in JSX
- style={{font-size:12,color:'red'}}
- style={{fontSize:'12px',color:'red'}}
- style={fontSize:'12px',color:'red'}
- style={{font-size:12px,color:'red'}}
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12/20
What are the advantages of ReactJS?
- Increases the application’s performance with Virtual DOM
- JSX makes code is easy to read and write
- It renders both on client and server side
- Easy to integrate with other frameworks(Angular, BackboneJS) since it is only a view library
- All of the above
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13/20
What is state in React?
- A persistant storage.
- An internal data store (object) of a component.
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14/20
What is ReactJS?
- Server side Framework
- User-interface framework
- A Library for building interaction interfaces
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15/20
What are the two ways that data gets handled in React?
- state & props
- services & components
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16/20
What are the disadvantages of ReactJS?
- It is only a view layer, you have still to plug your code for Ajax requests, events and so on. Some people get surprised by that.
- The library itself is pretty large.
- The learning curve can be steep.
- All of the above
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17/20
Choose the right answer about JSX
- JSX is faster because it performs optimization while compiling code to JavaScript
- JSX is a syntax notation for JavaScript XML
- JSX provides expressiveness of JavaScript along with HTML like template syntax.
- All of the above
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18/20
React merges the object you provide into the current state using
- setState()
- State()
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19/20
Arbitrary inputs of components are called
- Keys
- Props
- Elements
- Ref
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20/20
ref is used to refer a element / component returned by
- react()
- render()
- reduce()
- refer()
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