JAVASCRIPT

map to array javascript

let map = new Map().set('a', 1).set('b', 2),
    array = Array.from(map, ([name, value]) => ({ name, value }));

console.log(array);

array map javascript

const array1 = [1, 4, 9, 16];

// pass a function to map
const map1 = array1.map(x => x * 2);

console.log(map1);
// expected output: Array [2, 8, 18, 32]

javascript converting an array into a map

const arr = ['a', 'b', 'c', 2, 3, 4];
const nwMap = new Map([...arr.entries()]); 

array map

const array1 = [1, 4, 9, 16];

// pass a function to map
const map1 = array1.map(x => x * 2);

console.log(map1);
// expected output: Array [2, 8, 18, 32]

array to map js

var arr = [
    { key: 'foo', val: 'bar' },
    { key: 'hello', val: 'world' }
];

var result = new Map(arr.map(i => [i.key, i.val]));

// When using TypeScript, need to specify type:
// var result = arr.map((i): [string, string] => [i.key, i.val])

// Unfortunately maps don't stringify well.  This is the contents in array form.
console.log("Result is: " + JSON.stringify([...result])); 
// Map {"foo" => "bar", "hello" => "world"}
 Run code snippet

array map

let numbers = [1, 2, 3, 4]
let filteredNumbers = numbers.map(function(_, index) {
  if (index < 3) {
     return num
  }
})
// index goes from 0, so the filterNumbers are 1,2,3 and undefined.
// filteredNumbers is [1, 2, 3, undefined]
// numbers is still [1, 2, 3, 4]

array.map

let arr = [1,2,3]

/*
  map accepts a callback function, and each value of arr is passed to the 
  callback function. You define the callback function as you would a regular
  function, you're just doing it inside the map function
  
  map applies the code in the callback function to each value of arr, 
  and creates a new array based on your callback functions return values
*/
let mappedArr = arr.map(function(value){
	return value + 1
})

// mappedArr is:
> [2,3,4]

JavaScript Array map()

const numbers1 = [45, 4, 9, 16, 25];
const numbers2 = numbers1.map(myFunction);

function myFunction(value, index, array) {
  return value * 2;
}

array.map

var x = [1,2,3,4].map( function(item) {return item * 10;});

array map

function square(arr) {
       const newArr = arr.map(x => x * x );
    return newArr ;
  
  //if you find this answer is useful ,
//upvote ⇑⇑ , so can the others benefit also . @mohammad alshraideh ( ͡~ ͜ʖ ͡°)

array map

let numbers = [1, 2, 3, 4]
let filteredNumbers = numbers.map(function(num, index) {
  if (index < 3) {
     return num
  }
})
// index goes from 0, so the filterNumbers are 1,2,3 and undefined.
// filteredNumbers is [1, 2, 3, undefined]
// numbers is still [1, 2, 3, 4]

javascript array map

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

const arrayWithMultipliedElems = array.map(elem => elem * 2);

console.log(arrayWithMultipliedElems); // [2, 8, 18, 32]

js array map

let A = [9000, 8500, 5500, 6500];
let B = A.map(function (value, index, array) {
    return value*2; // forEach 沒有在 return 的，所以不會有作用
});
console.log(B); // undefined