Array.prototype.reduceRight()
and Array.prototype.some()
to create an array containing only the last unique occurrence of each value, based on the comparator function, fn
.const uniqueElementsByRight = (arr, fn) => arr.reduceRight((acc, v) => { if (!acc.some(x => fn(v, x))) acc.push(v); return acc; }, []);
uniqueElementsByRight( [ { id: 0, value: 'a' }, { id: 1, value: 'b' }, { id: 2, value: 'c' }, { id: 1, value: 'd' }, { id: 0, value: 'e' } ], (a, b) => a.id == b.id ); // [ { id: 0, value: 'e' }, { id: 1, value: 'd' }, { id: 2, value: 'c' } ]
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