lo/docs/data/core-findduplicatesbyerr.md

name, slug, sourceRef, category, subCategory, playUrl, signatures, variantHelpers, similarHelpers, position

name	slug	sourceRef	category	subCategory	playUrl	signatures	variantHelpers	similarHelpers	position
FindDuplicatesByErr	findduplicatesbyerr	find.go#L296	core	find	https://go.dev/play/p/HiVILQqdFP0	func FindDuplicatesByErr[T any, U comparable, Slice ~[]T](collection Slice, iteratee func(item T) (U, error)) (Slice, error)	core#find#findduplicatesbyerr	core#find#findduplicatesby core#find#findduplicates core#find#finduniques core#find#finduniquesby	135

Returns a slice with the first occurrence of each duplicated element by key, preserving order. The iteratee can return an error to stop iteration immediately.

result, err := lo.FindDuplicatesByErr([]int{3, 4, 5, 6, 7}, func(i int) (int, error) {
    return i % 3, nil
})
// []int{3, 4}, <nil>

Example with error:

result, err := lo.FindDuplicatesByErr([]int{3, 4, 5, 6, 7}, func(i int) (int, error) {
    if i == 5 {
        return 0, fmt.Errorf("number 5 is not allowed")
    }
    return i % 3, nil
})
// []int(nil), error("number 5 is not allowed")