Add utils.MapKeys and utils.MapValues (#19)

* Add utils.MapKeys and utils.MapValues

* Update map_values.go

utils/map_keys.go

@@ -0,0 +1,10 @@
+package utils
+
+// MapKeys returns all keys in a given map, **the order will not be stable, you should sort these values if needed.**
+func MapKeys[K comparable, V any](v map[K]V) []K {
+	resp := make([]K, 0, len(v))
+	for k := range v {
+		resp = append(resp, k)
+	}
+	return resp
+}

utils/map_keys_test.go

@@ -0,0 +1,30 @@
+package utils_test
+
+import (
+	"sort"
+	"testing"
+
+	"github.com/aidenwallis/go-utils/internal/assert"
+	"github.com/aidenwallis/go-utils/utils"
+)
+
+func TestMapKeys(t *testing.T) {
+	t.Parallel()
+
+	out := []int{1, 2, 3}
+	in := map[int]struct{}{
+		1: {},
+		2: {},
+		3: {},
+	}
+
+	v := utils.MapKeys(in)
+	sort.SliceStable(v, func(i, j int) bool {
+		return v[i] < v[j]
+	})
+
+	assert.Equal(t, 3, len(v))
+	for i := range out {
+		assert.Equal(t, out[i], v[i])
+	}
+}

utils/map_values.go

@@ -0,0 +1,10 @@
+package utils
+
+// MapValues returns all values in a given map, **the order is not stable, you should sort it if you need a stable order.**
+func MapValues[K comparable, V any](in map[K]V) []V {
+	out := make([]V, 0, len(in))
+	for _, v := range in {
+		out = append(out, v)
+	}
+	return out
+}

utils/map_values_test.go

@@ -0,0 +1,30 @@
+package utils_test
+
+import (
+	"sort"
+	"testing"
+
+	"github.com/aidenwallis/go-utils/internal/assert"
+	"github.com/aidenwallis/go-utils/utils"
+)
+
+func TestMapValues(t *testing.T) {
+	t.Parallel()
+
+	out := []int{1, 2, 3}
+	in := map[string]int{
+		"one":   1,
+		"two":   2,
+		"three": 3,
+	}
+
+	v := utils.MapValues(in)
+	sort.SliceStable(v, func(i, j int) bool {
+		return v[i] < v[j]
+	})
+
+	assert.Equal(t, 3, len(v))
+	for i := range out {
+		assert.Equal(t, out[i], v[i])
+	}
+}