Resolve #601

Shorter and sweeter

snippets/zipWith.md

@@ -2,22 +2,20 @@
 
 Creates an array of elements, grouped based on the position in the original arrays and using function as the last value to specify how grouped values should be combined.
 
-Check if the last argument provided in a function.
+Check if the last argument provided is a function.
 Use `Math.max()` to get the longest array in the arguments.
 Creates an array with that length as return value and use `Array.from()` with a map-function to create an array of grouped elements.
 If lengths of the argument-arrays vary, `undefined` is used where no value could be found.
 The function is invoked with the elements of each group `(...group)`.
 
 ```js
-const zipWith = (...arrays) => {
-  const length = arrays.length;
-  let fn = length > 1 ? arrays[length - 1] : undefined;
-  fn = typeof fn == 'function' ? (arrays.pop(), fn) : undefined;
-  const maxLength = Math.max(...arrays.map(x => x.length));
-  const result = Array.from({ length: maxLength }).map((_, i) => {
-    return Array.from({ length: arrays.length }, (_, k) => arrays[k][i]);
-  });
-  return fn ? result.map(arr => fn(...arr)) : result;
+const zipWith = (...array) => {
+  const fn = typeof array[array.length - 1] === 'function' ? array.pop() : undefined;
+  return Array
+    .from(
+      { length: Math.max(...array.map(a => a.length)) },
+      (_, i) => (fn ? fn(...array.map(a => a[i])) : array.map(a => a[i])),
+    );
 };
 ```