Add array/chunk method (#42)

* Add chunk method

* Add description

* Update after code review

* Update after code review

Co-authored-by: krystianborucinski <krystian.borucinski@sandstream.pl>

Author: 2 people

README.md

@@ -58,6 +58,30 @@ Checks if given arguments are all `Arrays`.
 ```
 <!-- prettier-ignore-end -->
 
+#### chunk
+
+Splits the given array into array of chunks of up to the given length.
+
+##### Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(count: number) => (xs: any[]) => any[]
+```
+<!-- prettier-ignore-end -->
+
+##### Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+chunk(2)(['a', 'b', 'c', 'd']); // ⇒ [['a', 'b'], ['c', 'd']]
+```
+
+```javascript
+chunk(3)(['a', 'b', 'c', 'd']); // ⇒ [['a', 'b', 'c'], ['d']]
+```
+<!-- prettier-ignore-end -->
+
 #### difference
 
 ##### Type signature

array/README.md

@@ -41,6 +41,30 @@ Checks if given arguments are all `Arrays`.
 ```
 <!-- prettier-ignore-end -->
 
+# chunk
+
+Splits the given array into array of chunks of up to the given length.
+
+## Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(count: number) => (xs: any[]) => any[]
+```
+<!-- prettier-ignore-end -->
+
+## Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+chunk(2)(['a', 'b', 'c', 'd']); // ⇒ [['a', 'b'], ['c', 'd']]
+```
+
+```javascript
+chunk(3)(['a', 'b', 'c', 'd']); // ⇒ [['a', 'b', 'c'], ['d']]
+```
+<!-- prettier-ignore-end -->
+
 # difference
 
 ## Type signature

array/chunk.js

@@ -0,0 +1,13 @@
+import range from "./range.js";
+
+export default count => xs => {
+  if (count > 0) {
+    const chunks = Math.ceil(xs.length / count);
+
+    return chunks > 0
+      ? range(chunks).map(i => xs.slice(i * count, (i + 1) * count))
+      : xs;
+  }
+
+  return [];
+};

array/chunk.json

@@ -0,0 +1,16 @@
+{
+  "name": "chunk",
+  "description": "Splits the given array into array of chunks of up to the given length.",
+  "signature": "(count: number) => (xs: any[]) => any[]",
+  "examples": [
+    {
+      "language": "javascript",
+      "content": "chunk(2)(['a', 'b', 'c', 'd']); // ⇒ [['a', 'b'], ['c', 'd']]"
+    },
+    {
+      "language": "javascript",
+      "content": "chunk(3)(['a', 'b', 'c', 'd']); // ⇒ [['a', 'b', 'c'], ['d']]"
+    }
+  ],
+  "questions": ["TODO: List questions that may this function answer."]
+}

array/chunk.md

@@ -0,0 +1,23 @@
+# chunk
+
+Splits the given array into array of chunks of up to the given length.
+
+## Type signature
+
+<!-- prettier-ignore-start -->
+```typescript
+(count: number) => (xs: any[]) => any[]
+```
+<!-- prettier-ignore-end -->
+
+## Examples
+
+<!-- prettier-ignore-start -->
+```javascript
+chunk(2)(['a', 'b', 'c', 'd']); // ⇒ [['a', 'b'], ['c', 'd']]
+```
+
+```javascript
+chunk(3)(['a', 'b', 'c', 'd']); // ⇒ [['a', 'b', 'c'], ['d']]
+```
+<!-- prettier-ignore-end -->

array/chunk.test.ts

@@ -0,0 +1,31 @@
+/* eslint-env jest */
+// @ts-ignore ambiguous import
+import chunk from "./chunk.ts";
+
+describe("chunk", () => {
+  it("should return an array of elements split into groups of the given length", () => {
+    expect(chunk(1)(["a", "b", "c", "d"])).toEqual([
+      ["a"],
+      ["b"],
+      ["c"],
+      ["d"]
+    ]);
+    expect(chunk(2)(["a", "b", "c", "d"])).toEqual([
+      ["a", "b"],
+      ["c", "d"]
+    ]);
+    expect(chunk(4)(["a", "b", "c", "d"])).toEqual([["a", "b", "c", "d"]]);
+  });
+
+  it("fills the final chunk with the remaining elements when the given array can't be split evenly", () => {
+    expect(chunk(3)(["a", "b", "c", "d"])).toEqual([["a", "b", "c"], ["d"]]);
+  });
+
+  it("should return an empty array when the chunk size is equal zero", () => {
+    expect(chunk(0)(["a", "b", "c", "d"])).toEqual([]);
+  });
+
+  it("should return an empty array when the given array is empty", () => {
+    expect(chunk(2)([])).toEqual([]);
+  });
+});

array/chunk.ts

@@ -0,0 +1,13 @@
+import range from "./range";
+
+export default (count: number) => (xs: any[]) => {
+  if (count > 0) {
+    const chunks = Math.ceil(xs.length / count);
+
+    return chunks > 0
+      ? range(chunks).map(i => xs.slice(i * count, (i + 1) * count))
+      : xs;
+  }
+
+  return [];
+};

array/index.js

@@ -1,5 +1,6 @@
 import any from "./any.js";
 import are from "./are.js";
+import chunk from "./chunk.js";
 import difference from "./difference.js";
 import differs from "./differs.js";
 import duplicates from "./duplicates.js";
@@ -45,6 +46,7 @@ import zipWith from "./zipWith.js";
 export {
   any,
   are,
+  chunk,
   difference,
   differs,
   duplicates,
@@ -91,6 +93,7 @@ export {
 export default {
   any,
   are,
+  chunk,
   difference,
   differs,
   duplicates,

array/index.ts

@@ -1,5 +1,6 @@
 import any from "./any";
 import are from "./are";
+import chunk from "./chunk";
 import difference from "./difference";
 import differs from "./differs";
 import duplicates from "./duplicates";
@@ -45,6 +46,7 @@ import zipWith from "./zipWith";
 export {
   any,
   are,
+  chunk,
   difference,
   differs,
   duplicates,
@@ -91,6 +93,7 @@ export {
 export default {
   any,
   are,
+  chunk,
   difference,
   differs,
   duplicates,