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Useful JavaScript Tricks

· One min read
ひかり
ひかり
Main bloger

Looping with indices using for​

for([i, e] of ["a", "b", "c"].entries()){
   console.log(i, e)
}

Also with forEach​

["a", "b", "c"].forEach((e, i) => {
   console.log(e, i)
})

Creating an array of length n​

const n = 10
let ary = [...Array(n)].map((_, i) => i)
// Or alternatively
ary = Array.from({length: n}).map((_, i)=> i)

Sum of an array​

let ary = [1, 2, 3, 4, 5]
ary.reduce((_, v) => _ + v)