Add direction property in flex class

- It's used when a layout needs to be changed according to the direction of a flex item.

- For example, when developing an UI component, you can use it to change the layout according to the direction of the super container view.

Author: gyuchan0128

README.md

@@ -755,6 +755,16 @@ Item natural size, considering only properties of the view itself. Independent o
 
 <br>
 
+### direction
+- Applies to: `flex items`
+
+**Property:**
+
+* **`direction`**  
+This `direction` property is get the direction flex items are placed in the flex container.
+
+<br>
+
 <a name="absolute_positioning"></a>
 ## 4. Absolute positioning  
 - Applies to: `flex items`

Sources/Swift/FlexLayout.swift

@@ -43,6 +43,19 @@ public final class Flex {
     public var intrinsicSize: CGSize {
         return yoga.intrinsicSize
     }
+
+    /**
+     This`direction` property is get the direction flex items are placed in the flex container.
+     */
+    public var direction: Direction? {
+        switch yoga.flexDirection {
+        case .column:           return Flex.Direction.column
+        case .columnReverse:    return Flex.Direction.columnReverse
+        case .row:              return Flex.Direction.row
+        case .rowReverse:       return Flex.Direction.rowReverse
+        @unknown default:       return nil
+        }
+    }
 
     init(view: UIView) {
         self.view = view