🔁 JS array looping

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There are a few different ways to loop over an array:

for Jump to heading

for (var i = 0; i < array.length; i++) {
  array[i]
}

    

forEach Jump to heading

array.forEach(function (i) {
  array[i]
})

    

for in Jump to heading

for (var i in array) {
  array[i]
}

    

for…of Jump to heading

for (var i of array) {
  array[i]
}

    

Test results Jump to heading

Test case name	Result
for	for x 4,680,671 ops/sec ±0.42% (68 runs sampled)
forEach	forEach x 5,043,765 ops/sec ±0.60% (67 runs sampled)
for in	for in x 9,155,750 ops/sec ±0.50% (68 runs sampled)
for…of	for…of x 1,339,234 ops/sec ±0.42% (68 runs sampled)

for...of uses @iterators internally which aren’t as efficient

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