Get unique values from array of objects

Question

I have an array of dynamic objects like that:

var arr = [
    {state: "FL"},
    {state: "NY"},
    {state: "FL"},
    {gender: "Male"},
    {state: "NY"},
    {gender: "Female"},
    {gender: "Female"},
    {year: "1990"}
]

How can I get just the unique objects?

The desired output is an array containing just the unique objects:

arr = [
    {state: "FL"},
    {state: "NY"},
    {gender: "Male"},
    {gender: "Female"},
    {year: "1990"}
]

I'm trying something like that using reduce, but on this way I need know the object key:

arr = arr.reduce((acc, curr) => 
    acc.find(e => e['state'] === curr['state']) ? acc : [...acc, curr], [])

It's not a duplicate because the other questions does not use "dynamic object" to get unique

Answer 1

You could stringify all objects, get the unique JSON and then convert the strings back to objects.

var array = [{ state: "FL" }, { state: "NY" }, { state: "FL" }, { gender: "Male" }, { state: "NY" }, { gender: "Female" }, { gender: "Female" }, { year: "1990" }],
    unique = Array.from(
        new Set(array.map(o => JSON.stringify(o))),
        s => JSON.parse(s)
    );
    
console.log(unique);

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If you have more than one key in the object and because if you have objects where the keys are in different order, I suggest you to get the entries first, sort this array, stringify it for a set, and then get the new objects back.

var array = [{ foo: 42, state: "FL" }, { state: "FL", foo: 42 }, { state: "FL" }, { state: "NY" }, { state: "FL" }, { gender: "Male" }, { state: "NY" }, { gender: "Female" }, { gender: "Female" }, { year: "1990" }],
    unique = Array.from(
        new Set(array.map(o => JSON.stringify(Object.entries(o).sort(([a], [b]) => a.localeCompare(b))))),
        s => Object.assign({}, ...JSON.parse(s).map(([k, v]) => ({ [k]: v })))
    );
    
console.log(unique);

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