js set contains code example

Example 1: 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 2: 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 3: check if set has value js

const mySet = new Set();

// Add value to set
mySet.add(15);

console.log(mySet.has(33)) // expected output: false
cosole.log(mySet.has(15)) // expected output: true

Example 4: add to set js

const mySet = new Set();

mySet.add(15);
mySet.add(33);
mySet.add(15);

for(let item of mySet) {
	console.log(item)
    // expected output: 15
	// expected output: 33
}

Example 5: set.contains in javascript

const set = new Set();

set.add(1);
set.add(2);
set.add(3);

console.log(set.has(2));  //true
console.log(set.has(4)); //false