// Use to remove duplicate elements from the array
const numbers = [2,3,4,4,2,3,3,4,4,5,5,6,6,7,5,32,3,4,5]
//spreading numbers of the object into an array using the new operator
console.log([...new Set(numbers)])
// [2, 3, 4, 5, 6, 7, 32]let mySet = new Set()
mySet.add(1) // Set [ 1 ]
mySet.add(5) // Set [ 1, 5 ]
mySet.add(5) // Set [ 1, 5 ]
mySet.add('some text') // Set [ 1, 5, 'some text' ]
let o = {a: 1, b: 2}
mySet.add(o)
mySet.add({a: 1, b: 2}) // o is referencing a different object, so this is okay
mySet.has(1) // true
mySet.has(3) // false, since 3 has not been added to the set
mySet.has(5) // true
mySet.has(Math.sqrt(25)) // true
mySet.has('Some Text'.toLowerCase()) // true
mySet.has(o) // true
mySet.size // 5
mySet.delete(5) // removes 5 from the set
mySet.has(5) // false, 5 has been removed
mySet.size // 4, since we just removed one value
console.log(mySet)
// logs Set(4) [ 1, "some text", {…}, {…} ] in Firefox
// logs Set(4) { 1, "some text", {…}, {…} } in Chrome
let text = 'India'
let mySet = new Set(text) // Set ['I', 'n', 'd', 'i', 'a']
mySet.size // 5
//case sensitive & duplicate ommision
new Set("Firefox") // Set(7) [ "F", "i", "r", "e", "f", "o", "x" ]
new Set("firefox") // Set(6) [ "f", "i", "r", "e", "o", "x" ]
// iterate over items in set
// logs the items in the order: 1, "some text", {"a": 1, "b": 2}, {"a": 1, "b": 2}
for (let item of mySet) console.log(item)
// logs the items in the order: 1, "some text", {"a": 1, "b": 2}, {"a": 1, "b": 2}
for (let item of mySet.keys()) console.log(item)
// logs the items in the order: 1, "some text", {"a": 1, "b": 2}, {"a": 1, "b": 2}
for (let item of mySet.values()) console.log(item)
// logs the items in the order: 1, "some text", {"a": 1, "b": 2}, {"a": 1, "b": 2}
// (key and value are the same here)
for (let [key, value] of mySet.entries()) console.log(key)
// convert Set object to an Array object, with Array.from
let myArr = Array.from(mySet) // [1, "some text", {"a": 1, "b": 2}, {"a": 1, "b": 2}]
// the following will also work if run in an HTML document
mySet.add(document.body)
mySet.has(document.querySelector('body')) // true
// converting between Set and Array
mySet2 = new Set([1, 2, 3, 4])
mySet2.size // 4
[...mySet2] // [1, 2, 3, 4]
// intersect can be simulated via
let intersection = new Set([...set1].filter(x => set2.has(x)))
// difference can be simulated via
let difference = new Set([...set1].filter(x => !set2.has(x)))
// Iterate set entries with forEach()
mySet.forEach(function(value) {
console.log(value)
})
// 1
// 2
// 3
// 4// create Set
const set1 = new Set(); // an empty set
console.log(set1); // Set {}
// Set with multiple types of value
const set2 = new Set([1, 'hello', {count : true}]);
console.log(set2); // Set {1, "hello", {count: true}}