Example 1: array to set javascript
const myArray = [1,2,3,1,5,8,1,2,9,4];
const unique = [...new Set(myArray)]; // [1, 2, 3, 5, 8, 9, 4]
const myString = ["a","b","c","a","d","b"];
const uniqueString = [...new Set(myString)]; //["a", "b", "c", "d"]
Example 2: set js
// 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]
Example 3: set in javascript
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
Example 4: set in javascript
// set is used for storing unique values
const firstSet = new Set([1, 2, 3]);
firstSet.add('hi'); //adding value to set
firstSet.add(3); //this will not give any error and it will also not be added
firstSet.delete('hi');//removing value from set
console.log(firstSet.has('hi'));//checking 'hi' is in the set or not
// showing all values in the set
console.log(firstSet);
for (const entry of firstSet.values()) {
console.log(entry);
Example 5: set js
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
Example 6: js new array from new set
return Array.from(new Set(this.posts.map(e => e.category)))