array foreach index code example

Example 1: javascript foreach index

users.forEach((user, index)=>{
	console.log(index); // Prints the index at which the loop is currently at
});

Example 2: javascript enumerate with index

const iterable = [...];
for (const [index, elem] in iterable.entries()) {
  f(index, elem);
}

// or
iterable.forEach((elem, index) => {
  f(index, elem);
});

Example 3: forEach index

const array1 = ['a', 'b', 'c'];

array1.forEach((element, index) => console.log(element, index));

Example 4: forEach

const arraySparse = [1,3,,7]
let numCallbackRuns = 0

arraySparse.forEach((element) => {
  console.log(element)
  numCallbackRuns++
})

console.log("numCallbackRuns: ", numCallbackRuns)

// 1
// 3
// 7
// numCallbackRuns: 3
// comment: as you can see the missing value between 3 and 7 didn't invoke callback function.