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JavaScript

Posted by Steven Gore
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Steven Gore
Full Stack JavaScript Techdegree Student 9,326 Points

Please explain how [...planets] can be used?

I originally had the code like this and it worked. But I noticed in the final project, [...planet] was used. I don't understand how this works.

My original working code without [...planet]

const Container = (props) => { return ( <div class="container"> {props.planets.map((p) => ( <Planet url={p.url} name={p.name} desc={p.desc} moons={p.moons} diameter={p.diameter} key={p.id} /> ))} </div> ); };

1 Answer

Robert Bourton
Robert Bourton
6,179 Points
Robert Bourton
Robert Bourton
6,179 Points

The Spread Operator There are many ways you can use the spread operator.

const numbers = [ 1, 2, 3 ]

function print( one, two, three) {
   console.log(one)
   console.log(two)
   console.log(three)
}

print( ...numbers )

function array( ...args ) {
   for (let i = 0; i < args.length; i++)
        console.log( args[i] )
}

array( 1, 2, 3)

const array1 = [ 1, 2, 3 ]
const array2 = [4, 5, 6 ]
const array3 = [ ...array1, ...array2 ]

let obj1 = { one: 1, two: 2 }
let obj2 = { three: 3, four: 4 }

let copy = { ...obj1 }
let merge = { ...obj1, ...obj2 }

I will need to see your whole code to help you out with this. Looks like your trying to build a HTML String.

Robert Bourton
Robert Bourton
6,179 Points
Robert Bourton
Robert Bourton
6,179 Points

I don't use semicolons in my JavaScript code, since they are optional.

Steven Parker
Steven Parker
231,236 Points
Steven Parker
Steven Parker
231,236 Points

Semicolons after statements may be technically optional, but they are most definitely a "best practice".
You might want to reconsider using them!   :speak_no_evil: