javascript es5 foreach code example

Example 1: js for each item do

let array = ['Item 1', 'Item 2', 'Item 3'];

array.forEach(item => {
	console.log(item); // Logs each 'Item #'
});

Example 2: javascript .foreach

let colors = ['red', 'blue', 'green'];
// idx and sourceArr optional; sourceArr == colors
colors.forEach(function(color, idx, sourceArr) {
	console.log(color, idx, sourceArr)
});
// Output:
// red 0 ['red', 'blue', 'green']
// blue 1 ['red', 'blue', 'green']
// green 2 ['red', 'blue', 'green']

Example 3: 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.