add pskl.utils.Array.chunk

src/js/utils/Array.js

@@ -10,6 +10,24 @@
         match = filtered[0];
       }
       return match;
+    },
+
+    chunk : function (array, chunks) {
+      var chunked = [];
+
+      // We cannot have more chunks than array items.
+      chunks = Math.min(chunks, array.length);
+
+      // chunks should be at least 1
+      chunks = Math.max(1, chunks);
+
+      var step = Math.round(array.length / chunks);
+      for (var i = 0 ; i < chunks ; i++) {
+        var isLast = i == chunks - 1;
+        var end = isLast ? array.length : (i + 1) * step;
+        chunked.push(array.slice(i * step, end));
+      }
+      return chunked;
     }
   };
 

test/js/utils/ArrayTest.js

@@ -0,0 +1,68 @@
+describe("Array utils", function() {
+
+  beforeEach(function() {});
+  afterEach(function() {});
+
+  it("chunks correctly", function() {
+    // when
+    var array = [1, 2, 3, 4];
+
+    // then
+    var chunks = pskl.utils.Array.chunk(array, 1);
+
+    // verify
+    expect(chunks.length).toBe(1);
+    expect(chunks[0]).toEqual([1, 2, 3, 4]);
+
+    // then
+    chunks = pskl.utils.Array.chunk(array, 2);
+
+    // verify
+    expect(chunks.length).toBe(2);
+    expect(chunks[0]).toEqual([1, 2]);
+    expect(chunks[1]).toEqual([3, 4]);
+
+    // then
+    chunks = pskl.utils.Array.chunk(array, 3);
+
+    // verify
+    expect(chunks.length).toBe(3);
+    expect(chunks[0]).toEqual([1]);
+    expect(chunks[1]).toEqual([2]);
+    expect(chunks[2]).toEqual([3, 4]);
+
+    // then
+    chunks = pskl.utils.Array.chunk(array, 4);
+
+    // verify
+    expect(chunks.length).toBe(4);
+    expect(chunks[0]).toEqual([1]);
+    expect(chunks[1]).toEqual([2]);
+    expect(chunks[2]).toEqual([3]);
+    expect(chunks[3]).toEqual([4]);
+
+    // then
+    chunks = pskl.utils.Array.chunk(array, 5);
+
+    // verify
+    expect(chunks.length).toBe(4);
+    expect(chunks[0]).toEqual([1]);
+    expect(chunks[1]).toEqual([2]);
+    expect(chunks[2]).toEqual([3]);
+    expect(chunks[3]).toEqual([4]);
+
+    // then
+    chunks = pskl.utils.Array.chunk(array, 0);
+
+    // verify
+    expect(chunks.length).toBe(1);
+    expect(chunks[0]).toEqual([1, 2, 3, 4]);
+
+    // then
+    chunks = pskl.utils.Array.chunk(array, -1);
+
+    // verify
+    expect(chunks.length).toBe(1);
+    expect(chunks[0]).toEqual([1, 2, 3, 4]);
+  });
+});