what is ~~ in map js; code example

Example 1: 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 2: javascript map

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 3: nodejs map

let wrongMap = new Map()
wrongMap['bla'] = 'blaa'
wrongMap['bla2'] = 'blaaa2'

console.log(wrongMap)  // Map { bla: 'blaa', bla2: 'blaaa2' }