Implement ChunkString (#188)

Implement ChunkString

README.md

@@ -122,6 +122,7 @@ Supported math helpers:
 Supported helpers for strings:
 
 - [Substring](#substring)
+- [ChunkString](#chunkstring)
 - [RuneLength](#runelength)
 
 Supported helpers for tuples:
@@ -978,6 +979,24 @@ sub := lo.Substring("hello", -2, math.MaxUint)
 // "lo"
 ```
 
+### ChunkString
+
+Returns an array of strings split into groups the length of size. If array can't be split evenly, the final chunk will be the remaining elements.
+
+```go
+lo.ChunkString("123456", 2)
+// []string{"12", "34", "56"}
+
+lo.ChunkString("1234567", 2)
+// []string{"12", "34", "56", "7"}
+
+lo.ChunkString("", 2)
+// []string{""}
+
+lo.ChunkString("1", 2)
+// []string{"1"}
+```
+
 ### RuneLength
 
 An alias to utf8.RuneCountInString which returns the number of runes in string.

string.go

@@ -1,6 +1,8 @@
 package lo
 
-import "unicode/utf8"
+import (
+	"unicode/utf8"
+)
 
 // Substring return part of a string.
 func Substring[T ~string](str T, offset int, length uint) T {
@@ -24,6 +26,36 @@ func Substring[T ~string](str T, offset int, length uint) T {
 	return str[offset : offset+int(length)]
 }
 
+// ChunkString returns an array of strings split into groups the length of size. If array can't be split evenly,
+// the final chunk will be the remaining elements.
+func ChunkString[T ~string](str T, size int) []T {
+	if size <= 0 {
+		panic("lo.ChunkString: Size parameter must be greater than 0")
+	}
+
+	if len(str) == 0 {
+		return []T{""}
+	}
+
+	if size >= len(str) {
+		return []T{str}
+	}
+
+	var chunks []T = make([]T, 0, ((len(str)-1)/size)+1)
+	currentLen := 0
+	currentStart := 0
+	for i := range str {
+		if currentLen == size {
+			chunks = append(chunks, str[currentStart:i])
+			currentLen = 0
+			currentStart = i
+		}
+		currentLen++
+	}
+	chunks = append(chunks, str[currentStart:])
+	return chunks
+}
+
 // RuneLength is an alias to utf8.RuneCountInString which returns the number of runes in string.
 func RuneLength(str string) int {
 	return utf8.RuneCountInString(str)

string_test.go

@@ -7,6 +7,32 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+func TestChunkString(t *testing.T) {
+	is := assert.New(t)
+
+	result1 := ChunkString("12345", 2)
+	is.Equal([]string{"12", "34", "5"}, result1)
+
+	result2 := ChunkString("123456", 2)
+	is.Equal([]string{"12", "34", "56"}, result2)
+
+	result3 := ChunkString("123456", 6)
+	is.Equal([]string{"123456"}, result3)
+
+	result4 := ChunkString("123456", 10)
+	is.Equal([]string{"123456"}, result4)
+
+	result5 := ChunkString("", 2)
+	is.Equal([]string{""}, result5)
+
+	result6 := ChunkString("明1好休2林森", 2)
+	is.Equal([]string{"明1", "好休", "2林", "森"}, result6)
+
+	is.Panics(func() {
+		ChunkString("12345", 0)
+	})
+}
+
 func TestSubstring(t *testing.T) {
 	is := assert.New(t)