I'm currently watching a video about getting unique values from an array object:

Javascript:

const menu = [
    {
        name: 'pancakes',
        category: 'breakfast',
    },
    {
        name: 'burger',
        category: 'lunch',
    },
    {
        name: 'steak',
        category: 'dinner',
    },
    {
        name: 'bacon',
        category: 'breakfast',
    },
    {
        name: 'eggs',
        category: 'breakfast',
    },
    {
        name: 'pasta',
        category: 'dinner',
    },
]

const categories = [...new Set(menu.map((item) => item.category))];

He wanted to get the unique category values (i.e. breakfast, lunch, dinner) and put them inside an array. So he first wanted to use map() to get every instance in the category, then use Set() to only get the unique value.

My question is: What does the [...] symbol mean (and what is it called)? I could not find anything on the internet about this.

Thanks!