feat(chunk)

src/chunk/__snapshots__/chunk.spec.ts.snap

@@ -0,0 +1,11 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`chunk function is a pure function 1`] = `
+Array [
+  1,
+  2,
+  3,
+  4,
+  5,
+]
+`;

src/chunk/chunk.spec.ts

@@ -0,0 +1,34 @@
+import { chunk } from './chunk';
+
+describe('chunk function', () => {
+  const input = [1, 2, 3, 4, 5];
+
+  test('is a pure function', () => {
+    chunk(2)(input);
+    expect(input).toMatchSnapshot();
+  });
+
+  test('[1, 2, 3, 4] |> chunk(2) === [[1, 2], [3, 4]]', () => {
+    expect(chunk<number>(2)([1, 2, 3, 4])).toEqual([[1, 2], [3, 4]]);
+  });
+
+  test('[1, 2, 3, 4, 5] |> chunk(2) === [[1, 2], [3, 4], [5]]', () => {
+    expect(chunk<number>(2)([1, 2, 3, 4, 5])).toEqual([[1, 2], [3, 4], [5]]);
+  });
+
+  test('[1, 2, 3, 4] |> chunk() === [[1], [2], [3], [4]]', () => {
+    expect(chunk<number>()([1, 2, 3, 4])).toEqual([[1], [2], [3], [4]]);
+  });
+
+  test('[1, 2, 3, 4] |> chunk(5) === [[1, 2, 3, 4]]', () => {
+    expect(chunk<number>(5)([1, 2, 3, 4])).toEqual([[1, 2, 3, 4]]);
+  });
+
+  test('[1, 2, 3, 4] |> chunk(0) === []', () => {
+    expect(chunk<number>(0)([1, 2, 3, 4])).toEqual([]);
+  });
+
+  test('[1, 2, 3, 4] |> chunk(-1) === []', () => {
+    expect(chunk<number>(-1)([1, 2, 3, 4])).toEqual([]);
+  });
+});

src/chunk/chunk.ts

@@ -0,0 +1,61 @@
+/**
+ * @module array=>array<array>
+ */
+/**
+ * This method chunk an array into multiple array of the same size,
+ * except the last one
+ * @param size The number elements by chunk.
+ * @return the function to apply on the TBD to do something
+ * @example
+ * ```
+ * chunk<number>(2)([1, 2, 3, 4]) // [[1, 2], [3, 4]]
+ * chunk<number>(2)([1, 2, 3, 4, 5]) // [[1, 2], [3, 4], [5]]
+ * ```
+ * @example Using the chain
+ * ```
+ * chain([1, 2, 3, 4])
+ *   .chain(chunk<number>(2))
+ *   .value() // [[1, 2], [3, 4]]
+ * ```
+ * @example default size is 1
+ * ```
+ * chunk<number>()([1, 2, 3, 4]) // [[1], [2], [3], [4]]
+ * ```
+ * @example when size is superior to input length
+ * ```
+ * chunk<number>(5)([1, 2, 3, 4]) // [[1, 2, 3, 4]]
+ * ```
+ * @example when size is 0
+ * ```
+ * chunk<number>(0)([1, 2, 3, 4]) // []
+ * ```
+ * @example when size is less than 0
+ * ```
+ * chunk<number>(-1)([1, 2, 3, 4]) // []
+ * ```
+ */
+export function chunk<T>(
+  size = 1
+): (element: ReadonlyArray<T>) => ReadonlyArray<ReadonlyArray<T>> {
+  if (size <= 0) {
+    return () => [];
+  }
+
+  return (array: ReadonlyArray<T>): ReadonlyArray<ReadonlyArray<T>> => {
+    const result: T[][] = [];
+    let counter = 0;
+    let accu: T[] = [];
+    for (let i = 0; i < array.length; i++) {
+      const element = array[i];
+      if (i !== 0 && 0 === counter % size) {
+        result.push(accu);
+        accu = [];
+      }
+      accu.push(element);
+      counter++;
+    }
+    result.push(accu);
+
+    return result;
+  };
+}

src/chunk/index.ts

@@ -0,0 +1 @@
+export * from './chunk';

src/taninsam.ts

@@ -2,6 +2,7 @@ export * from './array-from-value';
 export * from './cast-to';
 export * from './chain';
 export * from './chain-fn';
+export * from './chunk';
 export * from './count-character';
 export * from './entries';
 export * from './every';