Return unique array values from an array inside an array of objects

Question

I can\'t find a similar question and I\'m a bit stuck. I have the following JSON array:

[
    {
        \"Name\": \"element1\",
        \"Attributes\": [\"1\         


        

Answer 1

Building on top of @dfsq answer, you could replace the two map and reduce with a single flatMap

var result = [
    {
        "Name": "element1",
        "Attributes": ["1", "2"]
    },

    {
        "Name": "element2",
        "Attributes": ["1","3" ]
    },
    {
        "Name": "element3",
        "Attributes": []
    }
]

// map & flatten to [ "1", "2", "1", "3" ]
.flatMap(item => item.Attributes)

// filter unique [ "1", "2", "3" ]
.filter((item, i, arr) => arr.indexOf(item) === i)

console.log(result)