feat: add find and search

find.go

@@ -0,0 +1,11 @@
+package slice
+
+// Find finds by using function `fn` and returns its value.
+func Find[T any](values []T, fn func(v T) bool) (v T, found bool) {
+	for i := 0; i < len(values); i++ {
+		if fn(values[i]) {
+			return values[i], true
+		}
+	}
+	return
+}

find_test.go

@@ -0,0 +1,49 @@
+package slice
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestFind(t *testing.T) {
+	type args struct {
+		values []int
+		fn     func(v int) bool
+	}
+	tests := []struct {
+		name      string
+		args      args
+		wantV     int
+		wantFound bool
+	}{
+		{
+			name: "find_int_should_succeed",
+			args: args{
+				values: []int{1, 2, 3, 4, 5},
+				fn:     func(v int) bool { return v == 5 },
+			},
+			wantV:     5,
+			wantFound: true,
+		},
+		{
+			name: "find_int_should_failed",
+			args: args{
+				values: []int{1, 2, 3, 4, 5},
+				fn:     func(v int) bool { return v == 6 },
+			},
+			wantV:     0,
+			wantFound: false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			gotV, gotFound := Find(tt.args.values, tt.args.fn)
+			if !reflect.DeepEqual(gotV, tt.wantV) {
+				t.Errorf("Find() gotV = %v, want %v", gotV, tt.wantV)
+			}
+			if gotFound != tt.wantFound {
+				t.Errorf("Find() gotFound = %v, want %v", gotFound, tt.wantFound)
+			}
+		})
+	}
+}

search.go

@@ -0,0 +1,11 @@
+package slice
+
+// Search searches by using function `fn` and returns its index.
+func Search[T any](values []T, fn func(v T) bool) int {
+	for i := 0; i < len(values); i++ {
+		if fn(values[i]) {
+			return i
+		}
+	}
+	return -1
+}

search_test.go

@@ -0,0 +1,31 @@
+package slice
+
+import "testing"
+
+func TestSearch(t *testing.T) {
+	type args struct {
+		values []int
+		fn     func(v int) bool
+	}
+	tests := []struct {
+		name string
+		args args
+		want int
+	}{
+		{
+			name: "search_int_should_succeed",
+			args: args{
+				values: []int{1, 2, 3, 4, 5},
+				fn:     func(v int) bool { return v == 3 },
+			},
+			want: 2,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := Search(tt.args.values, tt.args.fn); got != tt.want {
+				t.Errorf("Search() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}