/* Answer to: "javascript map function" */

​

/*

  <Array>.map() - One of the most useful in-built methods in JavaScript (imo).

​

  The map() method creates a new array populated with the results of calling

  a provided function on every element in the calling array.

  For more information, click on the source link.

​

  Let me make some examples of it's uses:

*/

​

let array = [1, 4, 9, 16];

array.map(num => num * 2); // [2, 8, 18, 32];

array.map(pounds => `£${pounds}.00`); // ["£1.00", "£4.00", "£9.00", "£16.00"];

array.map(item => Math.sqrt(item)); // [1, 2, 3, 4];

array.map((item) => {

  return item * 2

} // an example that will map through a a list of items and return a new array with the item multiplied by 2

const numbers = [1, 2, 3, 4, 5]; 

​

const bigNumbers = numbers.map(number => {

  return number * 10;

});

const array = [2, 5, 9];

let squares = array.map((num) => num * num);

​

console.log(array); // [2, 5, 9]

console.log(squares); // [4, 25, 81]

// make new array from edited items of another array

var newArray = unchangedArray.map(function(item, index){

  return item;  // do something to returned item

});

​

// same in ES6 style (IE not supported)

var newArray2 = unchangedArray.map((item, index) => item);

const numbers = [0,1,2,3];

​

console.log(numbers.map((number) => {

  return number;

}));

const items = [1, 2, 3, 4, 5, 6, 7, 8, 9];

​

const anotherItems = items.map(item => item * 2);

​

console.log(anotherItems);

const numbers = [2, 4, 6, 8];

const result = numbers.map(a => a * 2);

console.log(result);

//Output: [ 4, 8, 12, 16 ]