Update "ArrayBuffer, binary arrays" files

Author: odsantos

4-binary/01-arraybuffer-binary-arrays/01-concat/_js.view/solution.js

@@ -2,9 +2,9 @@ function concat(arrays) {
   // sum of individual array lengths
   let totalLength = arrays.reduce((acc, value) => acc + value.length, 0);
 
-  if (!arrays.length) return null;
-
   let result = new Uint8Array(totalLength);
+  
+  if (!arrays.length) return result;
 
   // for each array - copy it over result
   // next array is copied right after the previous one

4-binary/01-arraybuffer-binary-arrays/article.md

@@ -30,7 +30,7 @@ Let's eliminate a possible source of confusion. `ArrayBuffer` has nothing in com
 
 **To manipulate an `ArrayBuffer`, we need to use a "view" object.**
 
-A view object does not store anything on it's own. It's the "eyeglasses" that give an interpretation of the bytes stored in the `ArrayBuffer`.
+A view object does not store anything on its own. It's the "eyeglasses" that give an interpretation of the bytes stored in the `ArrayBuffer`.
 
 For instance:
 
@@ -71,7 +71,7 @@ for(let num of view) {
 
 ## TypedArray
 
-The common term for all these views (`Uint8Array`, `Uint32Array`, etc) is [TypedArray](https://tc39.github.io/ecma262/#sec-typedarray-objects). They share the same set of methods and properities.
+The common term for all these views (`Uint8Array`, `Uint32Array`, etc) is [TypedArray](https://tc39.github.io/ecma262/#sec-typedarray-objects). They share the same set of methods and properties.
 
 Please note, there's no constructor called `TypedArray`, it's just a common "umbrella" term to represent one of views over `ArrayBuffer`: `Int8Array`, `Uint8Array` and so on, the full list will soon follow.