Add HasString and PluckString to slice pkg

pkg/slice/strings.go

@@ -23,3 +23,32 @@ func ToStringBoolMap(s []string) (h map[string]bool) {
 
 	return
 }
+
+func HasString(ss []string, s string) bool {
+	for i := range ss {
+		if ss[i] == s {
+			return true
+		}
+	}
+
+	return false
+}
+
+// RemoveString removes one or more strings form the input slice
+func PluckString(ss []string, ff ...string) (o []string) {
+	if len(ff) == 0 {
+		return ss
+	}
+
+	f := ToStringBoolMap(ff)
+	o = make([]string, 0, len(ss))
+
+	for _, s := range ss {
+		if !f[s] {
+			// remove from the list
+			o = append(o, s)
+		}
+	}
+
+	return o
+}

pkg/slice/strings_test.go

@@ -0,0 +1,152 @@
+package slice
+
+import (
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestIntersectStrings(t *testing.T) {
+	cases := []struct {
+		name string
+		a    []string
+		b    []string
+		c    []string
+	}{
+		{
+			"empty",
+			[]string{},
+			[]string{},
+			[]string{},
+		},
+		{
+			"none",
+			[]string{"a"},
+			[]string{"b"},
+			[]string{},
+		},
+		{
+			"some",
+			[]string{"a", "b"},
+			[]string{"a", "c"},
+			[]string{"a"},
+		},
+		{
+			"all",
+			[]string{"a", "b"},
+			[]string{"a", "b"},
+			[]string{"a", "b"},
+		},
+		{
+			"dups",
+			[]string{"a", "b", "b", "b"},
+			[]string{"a", "b"},
+			[]string{"a", "b"},
+		},
+	}
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			assert.EqualValues(t, IntersectStrings(c.a, c.b), c.c)
+		})
+	}
+}
+
+func TestToStringBoolMap(t *testing.T) {
+	cases := []struct {
+		name string
+		i    []string
+		o    map[string]bool
+	}{
+		{
+			"empty",
+			[]string{},
+			map[string]bool{},
+		},
+		{
+			"some",
+			[]string{"a"},
+			map[string]bool{"a": true},
+		},
+		{
+			"many",
+			[]string{"a", "b", "c", "c", "d"},
+			map[string]bool{"a": true, "b": true, "c": true, "d": true},
+		},
+	}
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			assert.EqualValues(t, ToStringBoolMap(c.i), c.o)
+		})
+	}
+}
+
+func TestHasString(t *testing.T) {
+	cases := []struct {
+		name string
+		ss   []string
+		s    string
+		o    bool
+	}{
+		{
+			"empty",
+			[]string{},
+			"a",
+			false,
+		},
+		{
+			"has not",
+			[]string{"a"},
+			"b",
+			false,
+		},
+		{
+			"has",
+			[]string{"a"},
+			"a",
+			true,
+		},
+	}
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			assert.EqualValues(t, HasString(c.ss, c.s), c.o)
+		})
+	}
+}
+
+func TestPluckStrung(t *testing.T) {
+	cases := []struct {
+		name string
+		ss   []string
+		ff   []string
+		o    []string
+	}{
+		{
+			"empty",
+			[]string{},
+			[]string{},
+			[]string{},
+		},
+		{
+			"some",
+			[]string{"a", "b"},
+			[]string{"a"},
+			[]string{"b"},
+		},
+		{
+			"all",
+			[]string{"a", "b"},
+			[]string{"a", "b"},
+			[]string{},
+		},
+		{
+			"not there",
+			[]string{"a"},
+			[]string{"b"},
+			[]string{"a"},
+		},
+	}
+	for _, c := range cases {
+		t.Run(c.name, func(t *testing.T) {
+			assert.EqualValues(t, HasString(c.ss, c.s), c.o)
+		})
+	}
+}