Merge branch 'oswaldom-code-feat-adding-chunk-map'

Author: samber

README.md

@@ -1329,6 +1329,27 @@ mergedMaps := lo.Assign(
 
 [[play](https://go.dev/play/p/VhwfJOyxf5o)]
 
+### ChunkEntries
+
+Splits a map into an array of elements in groups of a length equal to its size. If the map cannot be split evenly, the final chunk will contain the remaining elements.
+
+```go
+maps := lo.ChunkEntries(
+    map[string]int{
+        "a": 1,
+        "b": 2,
+        "c": 3,
+        "d": 4,
+        "e": 5,
+    },
+    3,
+)
+// []map[string]int{
+//    {"a": 1, "b": 2, "c": 3},
+//    {"d": 4, "e": 5},
+// }
+```
+
 ### MapKeys
 
 Manipulates a map keys and transforms it to a map of another type.

map.go

@@ -247,6 +247,46 @@ func Assign[K comparable, V any, Map ~map[K]V](maps ...Map) Map {
 	return out
 }
 
+// ChunkEntries splits a map into an array of elements in groups of a length equal to its size. If the map cannot be split evenly,
+// the final chunk will contain the remaining elements.
+func ChunkEntries[K comparable, V any](m map[K]V, size int) []map[K]V {
+	if size <= 0 {
+		panic("The chunk size must be greater than 0")
+	}
+
+	keys := make([]K, 0, len(m))
+	for key := range m {
+		keys = append(keys, key)
+	}
+
+	if len(keys) == 0 {
+		return []map[K]V{}
+	}
+
+	chunksNum := len(keys) / size
+	if len(keys)%size != 0 {
+		chunksNum += 1
+	}
+
+	result := make([]map[K]V, 0, chunksNum)
+
+	for i := 0; i < chunksNum; i++ {
+		start := i * size
+		end := (i + 1) * size
+		if end > len(keys) {
+			end = len(keys)
+		}
+
+		chunk := make(map[K]V)
+		for _, key := range keys[start:end] {
+			chunk[key] = m[key]
+		}
+		result = append(result, chunk)
+	}
+
+	return result
+}
+
 // MapKeys manipulates a map keys and transforms it to a map of another type.
 // Play: https://go.dev/play/p/9_4WPIqOetJ
 func MapKeys[K comparable, V any, R comparable](in map[K]V, iteratee func(value V, key K) R) map[R]V {

map_example_test.go

@@ -168,6 +168,26 @@ func ExampleAssign() {
 	// Output: 3 1 3 4
 }
 
+func ExampleChunkEntries() {
+	result := ChunkEntries(
+		map[string]int{
+			"a": 1,
+			"b": 2,
+			"c": 3,
+			"d": 4,
+			"e": 5,
+		},
+		3,
+	)
+
+	for i := range result {
+		fmt.Printf("%d\n", len(result[i]))
+	}
+	// Output:
+	// 3
+	// 2
+}
+
 func ExampleMapKeys() {
 	kv := map[int]int{1: 1, 2: 2, 3: 3, 4: 4}
 

map_test.go

@@ -332,6 +332,52 @@ func TestAssign(t *testing.T) {
 	is.IsType(after, before, "type preserved")
 }
 
+func TestChunkEntries(t *testing.T) {
+	t.Parallel()
+	is := assert.New(t)
+
+	result1 := ChunkEntries(map[string]int{"a": 1, "b": 2, "c": 3, "d": 4, "e": 5}, 2)
+	result2 := ChunkEntries(map[string]int{"a": 1, "b": 2, "c": 3, "d": 4, "e": 5}, 3)
+	result3 := ChunkEntries(map[string]int{}, 2)
+	result4 := ChunkEntries(map[string]int{"a": 1}, 2)
+	result5 := ChunkEntries(map[string]int{"a": 1, "b": 2}, 1)
+
+	expectedCount1 := 3
+	expectedCount2 := 2
+	expectedCount3 := 0
+	expectedCount4 := 1
+	expectedCount5 := 2
+
+	is.Len(result1, expectedCount1)
+	is.Len(result2, expectedCount2)
+	is.Len(result3, expectedCount3)
+	is.Len(result4, expectedCount4)
+	is.Len(result5, expectedCount5)
+
+	is.PanicsWithValue("The chunk size must be greater than 0", func() {
+		ChunkEntries(map[string]int{"a": 1}, 0)
+	})
+	is.PanicsWithValue("The chunk size must be greater than 0", func() {
+		ChunkEntries(map[string]int{"a": 1}, -1)
+	})
+
+	type myStruct struct {
+		Name  string
+		Value int
+	}
+
+	allStructs := []myStruct{{"one", 1}, {"two", 2}, {"three", 3}}
+	nonempty := ChunkEntries(map[string]myStruct{"a": allStructs[0], "b": allStructs[1], "c": allStructs[2]}, 2)
+	is.Len(nonempty, 2)
+
+	originalMap := map[string]int{"a": 1, "b": 2, "c": 3, "d": 4, "e": 5}
+	result6 := ChunkEntries(originalMap, 2)
+	for k := range result6[0] {
+		result6[0][k] = 10
+	}
+	is.Equal(originalMap, map[string]int{"a": 1, "b": 2, "c": 3, "d": 4, "e": 5})
+}
+
 func TestMapKeys(t *testing.T) {
 	t.Parallel()
 	is := assert.New(t)