如何遍历 javascript 中的这个对象数组？

Question

I have an array of objects here:

const users = [
    {
        name: 'xyz',
        claims: [
            {"location": 'dallas',
            "id": '123'},
            {"location": 'frisco',
            "id": '123'},
            {"location": 'plano',
            "id": '123'},
        ]
    },
    {
        name: 'abc',
        claims: [
            {"location": 'richardson',
            "id": '123'},
            {"location": 'rowlett',
            "id": '123'},
            {"location": 'dallas',
            "id": '123'},
        ]
    },
    {
        name: 'adr',
        claims: [
            {"location": 'frisco',
            "id": '123'},
            {"location": 'irving',
            "id": '123'},
            {"location": 'dallas',
            "id": '123'},
        ]
    }
]

I want to get all the locations with dallas as the value. How can I do that? I know I would probably use a loop (maybe a forEach) but I am not exactly sure how I could get the values that I need. Would I use filter?

Answer 1

Use flatMap with combination of filter :

const dallasLocations = users.flatMap(user => {
    return user.claims.filter(claim => claim.location === 'dallas')
})

Answer 2

You can use flatMap to flatten the mapped array after filtering the locations which equal to dallas .

 const users = [ { name: 'xyz', claims: [ {"location": 'dallas', "id": '123'}, {"location": 'frisco', "id": '123'}, {"location": 'plano', "id": '123'}, ] }, { name: 'abc', claims: [ {"location": 'richardson', "id": '123'}, {"location": 'rowlett', "id": '123'}, {"location": 'dallas', "id": '123'}, ] }, { name: 'adr', claims: [ {"location": 'frisco', "id": '123'}, {"location": 'irving', "id": '123'}, {"location": 'dallas', "id": '123'}, ] } ] const result = users.flatMap(u => u.claims.filter(c => c.location === 'dallas')) console.log(result)