Update README.md

Author: afontcu

README.md

@@ -158,7 +158,7 @@ By default detected QR codes are visually highlighted. A transparent canvas over
 
 You can also pass a function with `track` to customize the way the location is painted. This function is called to produce each frame. It receives the location object as the first argument and a `CanvasRenderingContext2D` instance as the second argument.
 
-> Avoid access to reactive properties in this function (like stuff in `data`, `computed` or your Vuex store). The function is called several times a second and might cause memory leaks. If you want to be save don't access `this` at all.
+> Avoid access to reactive properties in this function (like stuff in `data`, `computed` or your Vuex store). The function is called several times a second and might cause memory leaks. If you want to be safe don't access `this` at all.
 
 Say you want to paint in a different color that better fits your overall page theme.