Add Defining State In A Simple Class Component as a react til

react/defining-state-in-a-simple-class-component.md

@@ -0,0 +1,50 @@
+# Defining State In A Simple Class Component
+
+Most class components start off with a constructor which does some
+initialization of the component including setting the components initial
+state. It might look something like the following:
+
+```javascript
+class MyComponent extends React.Component {
+  constructor(props) {
+    super(props);
+    this.state = {
+      loading: true
+    };
+  }
+
+  render() {
+    if (this.state.loading) {
+      return (
+        <p>Loading...</p>
+      );
+    } else {
+      // ...
+    }
+  }
+}
+```
+
+If setting state is the only thing you need to do in the constructor,
+then you can skip the constructor all together.
+
+```javascript
+class MyComponent extends React.Component {
+  state = {
+    loading: true
+  };
+
+  render() {
+    if (this.state.loading) {
+      return (
+        <p>Loading...</p>
+      );
+    } else {
+      // ...
+    }
+  }
+}
+```
+
+This second example will work the same as the first, and it is a bit more
+concise.