arr.forEach(function(part, index, theArray) {

  theArray[index] = "hello world";

});

​

​

​

const originalArr = ["Iron", "Super", "Ant", "Aqua"];

const modifiedArr = originalArr.map(name => `${name}man`);

​

console.log( "Original: %s", originalArr );

console.log( "Modified: %s", modifiedArr );

​

const originalArr = ["Iron", "Super", "Ant", "Aqua"];

originalArr.forEach((name, index) => originalArr[index] = `${name}man`);

​

console.log( "Overridden: %s", originalArr );

data.forEach( (item, i, self) => self[i] = item + 10 );

​