add < Set < JavaScript

The add() method of a Set inserts a new element with a specified value in to the set, if there isn't an element with the same value in the set already,

    
    const months = new Set(['Jan', 'Feb']);

    months.add('Dec');

    for (const month of months) {
      console.log(month);
    }
    // "Jan"
    // "Feb"
    // "Dec"