fleshed out up to step 6

step06/src/components/TodoHeader.tsx

@@ -0,0 +1,21 @@
+import React from "react";
+
+export class TodoHeader extends React.Component<any, any> {
+  render() {
+    const { filter } = this.props;
+    return (
+      <div>
+        <h1>todos</h1>
+        <input className="textfield" />
+        <button className="button add">Add</button>
+        <div className="filter">
+          <button className={filter == "all" ? "active" : ""}>all</button>
+          <button className={filter == "active" ? "active" : ""}>active</button>
+          <button className={filter == "completed" ? "active" : ""}>
+            completed
+          </button>
+        </div>
+      </div>
+    );
+  }
+}