How to Remove Duplicate Objects from Arrays in JavaScript

const duplicates = [
    { key: 'apple',  value: '🍎' },
    { key: 'banana', value: '🍌' },
    { key: 'banana', value: '🍌' }
]

const set = new Set()
const unique = duplicates.filter(item => {
    const alreadyHas = set.has(item.key)
    set.add(item.key)

    return !alreadyHas
})

// ❌ This won't work
[...new Set(duplicates)]

// Because the reference will be different, even if the properties match
{ id: 1 } !== { id: 1 }

const removeDuplicateObjects = (array, key) => {
    const set = new Set()

    return array.filter(item => {
        const alreadyHas = set.has(item[key])
        set.add(item[key])

        return !alreadyHas
    })
}

// Later call it in your app like so:
removeDuplicateObjects(array, 'key') <- looks for the "key" property
removeDuplicateObjects(array, 'value') <- looks for the "value" property