Fix typos

step1-06/demo/README.md

@@ -1,10 +1,10 @@
 # Creating a State Driven UI
 
-In React data travels two directions, top down in the form of state propegating throughout controls, and bottom up, as interacting with the UI flows back up to modify the state. When writing an application it's often helpful to think of these two directions as separate parts of the development process.
+In React data travels two directions, top down in the form of state propagating throughout controls, and bottom up, as interacting with the UI flows back up to modify the state. When writing an application it's often helpful to think of these two directions as separate parts of the development process.
 
 ## demo
 
-[Step #3 of Thinking in React](https://reactjs.org/docs/thinking-in-react.html) suggests finding the "minimal set of mutable state" that your application requires. So in this demo we are going to add that "minimal state" to our application and drive our UI off of that data. With that done the next step will be to create ways to modify that state, which will in turn cascade down through our UI. This [reconcilation](https://reactjs.org/docs/reconciliation.html) process, figuring out what in your UI needs to change based on changing state, is what React excels in.
+[Step #3 of Thinking in React](https://reactjs.org/docs/thinking-in-react.html) suggests finding the "minimal set of mutable state" that your application requires. So in this demo we are going to add that "minimal state" to our application and drive our UI off of that data. With that done the next step will be to create ways to modify that state, which will in turn cascade down through our UI. This [reconciliation](https://reactjs.org/docs/reconciliation.html) process, figuring out what in your UI needs to change based on changing state, is what React excels in.
 
 ### Adding State to App
 
@@ -75,11 +75,11 @@ I've already pulled out our props into `filter` and `todos` variables, and writt
 - We use the `id` from the `filterTodos` array as the [list key](https://reactjs.org/docs/lists-and-keys.html) to help React track each item as state changes.
 - The key is not actually passed into the component, so we pass the key in as `id` as well. This will help us out later.
 - Lastly we use the `id` to grab the todo from our `todos` object, then use the [spread operator](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_syntax) to pass through the todo's `label` and `completed` values.
-  > This spread opperator is the same as saying `label={todos[id].label} completed={todos[id].completed}`. Pretty obvious why spread is so handy!
+  > This spread operator is the same as saying `label={todos[id].label} completed={todos[id].completed}`. Pretty obvious why spread is so handy!
 
 ### State Driven and Stateful Header
 
-Within the header we've got a situation where we not only want to pass `filter` state down to it, but we also want to maintain state within the control. Fortunatly, this is no problem at all for React. First off let's deal with the incoming state.
+Within the header we've got a situation where we not only want to pass `filter` state down to it, but we also want to maintain state within the control. Fortunately, this is no problem at all for React. First off let's deal with the incoming state.
 
 #### Conditional ClassNames
 
@@ -93,9 +93,9 @@ In CSS based styling, visual states are applied by adding and removing classes.
 </nav>
 ```
 
-> Terniary operators are very popular in React code as each expression could be a string for a className, or even a JSX element.
+> Ternary operators are very popular in React code as each expression could be a string for a className, or even a JSX element.
 
-#### Creating a Controled Input
+#### Creating a Controlled Input
 
 In tradition HTML forms users interact with the form, and on submit, those values are captured and transmitted. Those are called **uncontrolled inputs**. A **controlled input** is one whos value is defined by state, and interaction with that input updates state with each keystroke. This round trip process might sound inefficient, but in reality it has little to no impact, and it enables some advanced form functionality.