loop through array and change value javascript code example

Example 1: foreach and replace item based on condition

arr.forEach(function(part, index, theArray) {
  theArray[index] = "hello world";
});

Example 2: foreach and replace item based on condition

arr.forEach(function(part, index) {
  this[index] = "hello world";
}, arr); // use arr as this

Example 3: forEach modify array JavaScript

arr.forEach(function(part, index) {
  this[index] = "hello world";
}, arr); // use arr as this