lo/docs/data/core-mapkeyserr.md

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

name	slug	sourceRef	category	subCategory	signatures	variantHelpers	similarHelpers	position
MapKeysErr	mapkeyserr	map.go#L293	core	map	func MapKeysErr[K comparable, V any, R comparable](in map[K]V, iteratee func(value V, key K) (R, error)) (map[R]V, error)	core#map#mapkeyserr	core#map#mapkeys core#map#mapvalueserr	185

Transforms map keys using a predicate while keeping values. Returns an error if the iteratee function fails, stopping iteration immediately.

in := map[int]int{1: 1, 2: 2, 3: 3}
out, err := lo.MapKeysErr(in, func(v int, _ int) (string, error) {
    if v == 2 {
        return "", fmt.Errorf("even number not allowed")
    }
    return strconv.Itoa(v), nil
})
// map[string]int(nil), error("even number not allowed")

in := map[int]int{1: 1, 2: 2, 3: 3}
out, err := lo.MapKeysErr(in, func(v int, _ int) (string, error) {
    return strconv.Itoa(v), nil
})
// map[string]int{"1":1, "2":2, "3":3}, nil