arr1.forEach(function (item) code example
Example 1: 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 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.