ES6 - Removing duplicates from array of objects

Question

Assuming an array of objects as follows:

const listOfTags = [     {id: 1, label: "Hello", color: "red", sorting: 0},     {id: 2, label: "World", color: "green", sorting: 1},     {id: 3, label: "Hello", color: "blue", sorting: 4},     {id: 4, label: "Sunshine", color: "yellow", sorting: 5},     {id: 5, label: "Hello", color: "red", sorting: 6}, ] 

A duplicate entry would be if label and color are the same. In this case Objects with id = 1 and id = 5 are duplicates.

How can I filter this array and remove duplicates?

I know solutions where you can filter against one key with something like:

const unique = [... new Set(listOfTags.map(tag => tag.label)] 

But what about multiple keys?

As per request in comment, here the desired result:

[     {id: 1, label: "Hello", color: "red", sorting: 0},     {id: 2, label: "World", color: "green", sorting: 1},     {id: 3, label: "Hello", color: "blue", sorting: 4},     {id: 4, label: "Sunshine", color: "yellow", sorting: 5}, ] 

Answer 1

You could use a Set in a closure for filtering.

const      listOfTags = [{ id: 1, label: "Hello", color: "red", sorting: 0 }, { id: 2, label: "World", color: "green", sorting: 1 }, { id: 3, label: "Hello", color: "blue", sorting: 4 }, { id: 4, label: "Sunshine", color: "yellow", sorting: 5 }, { id: 5, label: "Hello", color: "red", sorting: 6 }],      keys = ['label', 'color'],      filtered = listOfTags.filter(          (s => o =>               (k => !s.has(k) && s.add(k))              (keys.map(k => o[k]).join('|'))          )          (new Set)      );    console.log(filtered);

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Answer 2

Late one, but I don't know why nobody suggests something much simpler:

listOfTags.filter((tag, index, array) => array.findIndex(t => t.color == tag.color && t.label == tag.label) == index);