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Discussion on: Remove Duplicates With Set() - Full-Stop

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Replies for: Does that work with array of objects, having similar properties?

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bytebodger profile image
Adam Nathaniel Davis • • Edited

As Vesa demonstrated, this only works on scalar values. The reason is pretty simple:

console.log({a: 1} === {a: 1}); // false
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You could kinda sorta get around this using the old JSON.stringify() hack:

const set1 = new Set([{ a: 1 }, { a: 1 }]);
console.log(set1.size); // 2

const set2 = new Set([JSON.stringify({ a: 1 }), JSON.stringify({ a: 1 })]);
console.log(set2.size); // 1

const set3 = new Set([['a'], ['a']]);
console.log(set3.size); // 2

const set4 = new Set([JSON.stringify(['a']), JSON.stringify(['a'])]);
console.log(set4.size); // 1
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Although that only "works" if the keys/elements are in the same order. It would also fail in any scenario where JSON.stringify() would fail - e.g., if the objects/arrays contain functions.