Looping over Arrays: for vs. for-in vs. .forEach() vs. for-of

This blog post compares four ways of looping over Arrays:

The for loop:
for (let index=0; index < someArray.length; index++) {
const elem = someArray[index];
// ···
}

The for-in loop:
for (const key in someArray) {
console.log(key);
}

…


This content originally appeared on 2ality – JavaScript and more and was authored by Dr. Axel Rauschmayer

This blog post compares four ways of looping over Arrays:

  • The for loop:

    for (let index=0; index < someArray.length; index++) {
  const elem = someArray[index];
  // ···
}

  • The for-in loop:

    for (const key in someArray) {
  console.log(key);
}

  • The Array method .forEach():

    someArray.forEach((elem, index) => {
  console.log(elem, index);
});

  • The for-of loop:

    for (const elem of someArray) {
  console.log(elem);
}

for-of is often the best choice. We’ll see why.

[Read rest of post]


This content originally appeared on 2ality – JavaScript and more and was authored by Dr. Axel Rauschmayer


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Dr. Axel Rauschmayer | Sciencx (2021-01-07T00:00:00+00:00) Looping over Arrays: for vs. for-in vs. .forEach() vs. for-of. Retrieved from https://www.scien.cx/2021/01/07/looping-over-arrays-for-vs-for-in-vs-foreach-vs-for-of/

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" » Looping over Arrays: for vs. for-in vs. .forEach() vs. for-of." Dr. Axel Rauschmayer | Sciencx - Thursday January 7, 2021, https://www.scien.cx/2021/01/07/looping-over-arrays-for-vs-for-in-vs-foreach-vs-for-of/
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» Looping over Arrays: for vs. for-in vs. .forEach() vs. for-of | Dr. Axel Rauschmayer | Sciencx | https://www.scien.cx/2021/01/07/looping-over-arrays-for-vs-for-in-vs-foreach-vs-for-of/ |

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