JAVASCRIPT

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]

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]

how to use the map method in javascript

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

const bigNumbers = numbers.map(number => {
  return number * 10;
});

array mdn map

let new_array = arr.map(function callback( currentValue[, index[, array]]) {
    // return element for new_array
}[, thisArg])

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]

map method js

// Map objects are collections of key-value pairs. 
// A key in the Map may only occur once, it is unique in the Map 's collection
let map = new Map()
let keyArray = 'Array'
map.set(keyArray, [1, 2, 3, 4, 5])
map.get(keyArray) // 1, 2, 3, 4, 5

JavaScript Array Methods .map()

let numbers = [1, 2, 3, 4, 5];
let doubles = numbers.map(number => number * 2)
console.log(doubles)
// --> [ 2, 4, 6, 8, 10 ]

map method

function map(array, transform) {
  let mapped = [];
  for (let element of array) {
    mapped.push(transform(element));
  }
  return mapped;
}

let rtlScripts = SCRIPTS.filter(s => s.direction == "rtl");
console.log(map(rtlScripts, s => s.name));
// → ["Adlam", "Arabic", "Imperial Aramaic", …]

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;});

.map method

// Arrow function
map((element) => { ... } )
map((element, index) => { ... } )
map((element, index, array) => { ... } )

// Callback function
map(callbackFn)
map(callbackFn, thisArg)

// Inline callback function
map(function callbackFn(element) { ... })
map(function callbackFn(element, index) { ... })
map(function callbackFn(element, index, array){ ... })
map(function callbackFn(element, index, array) { ... }, thisArg)

map method

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 ͡°)

.map() method on arrays

arr.map(function(el, i){
return ...
})

javaScript Map() Method

// Create a Map
const fruits = new Map([
  ["apples", 500],
  ["bananas", 300],
  ["oranges", 200]
]);

js map()

var number = [1, 2 , 3, 4, 5, 6, 7, 8, 9]; 
var doubles  = number.map((n) => { return n*2 })

/*  doubles 
    (9) [2, 4, 6, 8, 10, 12, 14, 16, 18] */

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]

map method

var yourArray= yourArray.map(Number);

map method

//// Write a function that takes an array of objects (courses) and returns object of 2 new arrays // first one is containing the names of all of the courses in the data set. // second one is containing the names of all the students
const getInfo = (arr) => {
  let coursesName = [];
  let studentsName = [];
  // write your code here

  return { coursesName, studentsName };
};

//if you find this answer is useful ,
//upvote ⇑⇑ , so can the others benefit also . @mohammad alshraideh ( ͡~ ͜ʖ ͡°)

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

Array.map method

const shoppingList = ['Oranges', 'Cassava', 'Garri', 'Ewa', 'Dodo', 'Books']

export default function List() {
  return (
    <>
      {shoppingList.map((item, index) => {
        return (
          <ol>
            <li key={index}>{item}</li>
          </ol>
        )
      })}
    </>
  )
}