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SPREAD IN JAVASCRIPT

michealadisa profile image Micheal Adisa ・1 min read

Oh i just finished washing my clothes i need them to be side by side on a line, i’ll spread them right? This sounds quite abstract, let’s see how this relates to javascript.

The javascript spread function is denoted by three dots ‘...’ (PS: Ignore the quotes). It was added to JavaScript in ES6 (ES2015) and is useful for adding items to an array, combining array and objects into a place and spreading an array out into a function’s arguments.

const array1 = [ 1, 2, 3, 4 , 5]
const array2 = [ 6, 7, 8, 9, 10]

newArray = [...array1, ...array2]
console.log(newArray) // [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

Just like that! Our spread function works well as expected. You can go on and on to combine lots of array together into one (side by side 😀)

Interesting stuff, it can also be used in Math functions.

const nums1 = [2, 7, 8, 5]
const nums2 = [4, 1, 9, 3]

const newNums = [...nums1, ...nums2]
console.log(Math.max(...newNums)); // 9
console.log(Math.min(...newNums)); // 1

If you tried to log newNums max number or minimum number without the spread syntax, you’ll get NaN.
Try this; console.log(Math.min(newNums)); // NaN
I’m sure you’re asking why this happened right?. Well, Math.max or Math.min and any other Math operator expects a list of numeric arguments, not a single array.

This actually gives us a javascript superpower, love to see it! 😀.

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michealadisa profile

Micheal Adisa

@michealadisa

I'm interested in technology, design and music!

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