Update snippet descriptions

snippets/initialize2DArray.md

@@ -5,8 +5,9 @@ tags: array,intermediate
 
 Initializes a 2D array of given width and height and value.
 
-- Use `Array.prototype.map()` to generate h rows where each is a new array of size w initialize with value.
-- If the value is not provided, default to `null`.
+- Use `Array.from()` and `Array.prototype.map()` to generate `h` rows where each is a new array of size `w`.
+- Use `Array.prototype.fill()` to initialize all items with value `val`.
+- Omit the last argument, `val`, to use a default value of `null`.
 
 ```js
 const initialize2DArray = (w, h, val = null) =>
@@ -14,5 +15,5 @@ const initialize2DArray = (w, h, val = null) =>
 ```
 
 ```js
-initialize2DArray(2, 2, 0); // [[0,0], [0,0]]
+initialize2DArray(2, 2, 0); // [[0, 0], [0, 0]]
 ```