foreach get index nodejs code example

Example 1: foreach javascript

let names = ['josh', 'joe', 'ben', 'dylan'];
// index and sourceArr are optional, sourceArr == ['josh', 'joe', 'ben', 'dylan']
names.forEach((name, index, sourceArr) => {
	console.log(color, idx, sourceArr)
});

// josh 0 ['josh', 'joe', 'ben', 'dylan']
// joe 1 ['josh', 'joe', 'ben', 'dylan']
// ben 2 ['josh', 'joe', 'ben', 'dylan']
// dylan 3 ['josh', 'joe', 'ben', 'dylan']

Example 2: 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.