Fix rendering fail due to Undefined, and spelling mistake

README.md

@@ -96,11 +96,11 @@ It is important then, that you know which variables are being parsed to the func
           segment: Segment {
             borderColor: 
               FnWithArgs::new() // Create the Function
-                .arg("ctx") // Add a named arguement using a builder pattern
+                .arg("ctx") // Add a named argument using a builder pattern
                 .body("ctx.p0.parsed.y > ctx.p1.parsed.y ? 'red' : 'green'") // Add the function body, in this case make the line red if the slope is negative
           }
         }
       ]
     }
   }
-```
+```

src/utils.rs

@@ -54,6 +54,9 @@ impl Chart {
 
                     let dash = Reflect::get(&segment, &"borderDash".into());
                     if let Ok(dash) = dash {
+                        if dash == JsValue::UNDEFINED {
+                            return;
+                        }
                         Reflect::set(
                             &segment,
                             &"borderDash".into(),
@@ -66,6 +69,9 @@ impl Chart {
 
                     let color = Reflect::get(&segment, &"borderColor".into());
                     if let Ok(color) = color {
+                        if color == JsValue::UNDEFINED {
+                            return;
+                        }
                         Reflect::set(
                             &segment,
                             &"borderColor".into(),