From d86be6ef9ca4dfbae92011d5d6cab759c9019512 Mon Sep 17 00:00:00 2001
From: tuannguyen <nguyenvantuan2391996@gmail.com>
Date: Sun, 6 Aug 2023 18:48:34 +0700
Subject: [PATCH] feat: add the func goDashMap

---
 collection/map.go      | 41 +++++++++++++++++++++
 collection/map_test.go | 82 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 123 insertions(+)
 create mode 100644 collection/map.go
 create mode 100644 collection/map_test.go

diff --git a/collection/map.go b/collection/map.go
new file mode 100644
index 0000000..de496d4
--- /dev/null
+++ b/collection/map.go
@@ -0,0 +1,41 @@
+package collection
+
+import (
+	"reflect"
+
+	"github.com/warriors-vn/go-dash/constants"
+)
+
+// goDashMap applies the iteratee function to each element in the input array and returns a new slice of results.
+// It takes an array-like data structure and an iteratee function that operates on each element.
+// The iteratee function should have the signature func(elementType) mappedElementType.
+// The function returns a new slice of mapped elements and an error if any occurs.
+func goDashMap(array, iteratee interface{}) (interface{}, error) {
+	arrValue, iterateeValue := reflect.ValueOf(array), reflect.ValueOf(iteratee)
+
+	if arrValue.Kind() != reflect.Slice && arrValue.Kind() != reflect.Array {
+		return nil, constants.ErrNotSlice
+	}
+
+	if iterateeValue.Kind() != reflect.Func {
+		return nil, constants.ErrNotFunction
+	}
+
+	numParams := iterateeValue.Type().NumIn()
+	if numParams != 1 {
+		return nil, constants.ErrNotSupport
+	}
+
+	kind, result := iterateeValue.Type().In(0).Kind(), reflect.MakeSlice(arrValue.Type(), 0, 0)
+	if kind == reflect.Interface {
+		return nil, constants.ErrNotSupport
+	}
+	for i := 0; i < arrValue.Len(); i++ {
+		res := iterateeValue.Call([]reflect.Value{reflect.ValueOf(arrValue.Index(i).Interface())})
+		if len(res) > 0 && res[0].Kind() == kind {
+			result = reflect.Append(result, res[0])
+		}
+	}
+
+	return result.Interface(), nil
+}
diff --git a/collection/map_test.go b/collection/map_test.go
new file mode 100644
index 0000000..5298ad8
--- /dev/null
+++ b/collection/map_test.go
@@ -0,0 +1,82 @@
+package collection
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/warriors-vn/go-dash/constants"
+)
+
+func Test_goDashMap_valid_int(t *testing.T) {
+	result, err := goDashMap([]int{1, 2, 3, 4}, func(n int) int {
+		return n * n
+	})
+
+	assert.Equal(t, []int{1, 4, 9, 16}, result)
+	assert.Nil(t, err)
+}
+
+func Test_goDashMap_valid_response_func_invalid(t *testing.T) {
+	result, err := goDashMap([]int{1, 2, 3, 4}, func(n int) bool {
+		return n%2 == 0
+	})
+
+	assert.Equal(t, []int{}, result)
+	assert.Nil(t, err)
+}
+
+func Test_goDashMap_valid_string(t *testing.T) {
+	result, err := goDashMap([]string{"a", "b", "c"}, func(n string) string {
+		return n + n
+	})
+
+	assert.Equal(t, []string{"aa", "bb", "cc"}, result)
+	assert.Nil(t, err)
+}
+
+func Test_goDashMap_valid_struct(t *testing.T) {
+	type User struct {
+		Name string
+		Age  int
+	}
+	result, err := goDashMap([]*User{{Name: "Kakalot", Age: 26}, {Name: "Vegeta", Age: 27}, {Name: "Trunk", Age: 10}}, func(n *User) *User {
+		return &User{Name: n.Name, Age: n.Age * 2}
+	})
+
+	assert.Equal(t, []*User{{Name: "Kakalot", Age: 52}, {Name: "Vegeta", Age: 54}, {Name: "Trunk", Age: 20}}, result)
+	assert.Nil(t, err)
+}
+
+func Test_goDashMap_invalid_array_not_slice(t *testing.T) {
+	result, err := goDashMap(true, func(n int) int {
+		return n * 2
+	})
+
+	assert.Equal(t, nil, result)
+	assert.Equal(t, constants.ErrNotSlice, err)
+}
+
+func Test_goDashMap_invalid_predicate_not_func(t *testing.T) {
+	result, err := goDashMap([]string{"a", "b", "c"}, true)
+
+	assert.Equal(t, nil, result)
+	assert.Equal(t, constants.ErrNotFunction, err)
+}
+
+func Test_goDashMap_invalid_param_predicate_limit(t *testing.T) {
+	result, err := goDashMap([]string{"a", "b", "c"}, func(n string, m int) bool {
+		return n == "a" || m%2 == 0
+	})
+
+	assert.Equal(t, nil, result)
+	assert.Equal(t, constants.ErrNotSupport, err)
+}
+
+func Test_goDashMap_invalid_interface(t *testing.T) {
+	result, err := goDashMap([]interface{}{"a", "b", "c"}, func(n interface{}) interface{} {
+		return n
+	})
+
+	assert.Equal(t, nil, result)
+	assert.Equal(t, constants.ErrNotSupport, err)
+}