Example 1: javascript map array
const myArray = ['Sam', 'Alice', 'Nick', 'Matt'];
// Appends text to each element of the array
const newArray = myArray.map(name => {
return 'My name is ' + name;
});
console.log(newArray); // ['My name is Sam', 'My Name is Alice', ...]
// Appends the index of each element with it's value
const anotherArray = myArray.map((value, index) => index + ": " + value);
console.log(anotherArray); // ['0: Sam', '1: Alice', '2: Nick', ...]
// Starting array is unchanged
console.log(myArray); // ['Sam', 'Alice', 'Nick', 'Matt']
Example 2: javascript map
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
Example 3: how to use the map method in javascript
const numbers = [1, 2, 3, 4, 5];
const bigNumbers = numbers.map(number => {
return number * 10;
});
Example 4: javascript map array
const sweetArray = [2, 3, 4, 5, 35]
const sweeterArray = sweetArray.map(sweetItem => {
return sweetItem * 2
})
console.log(sweeterArray)
Example 5: 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]
Example 6: array map
let numbers = [1, 4, 9]
let roots = numbers.map(function(num) {
return Math.sqrt(num)
})
// roots is now [1, 2, 3]
// numbers is still [1, 4, 9]