Warn on lack of App/Window and passing children to Button

src/components/Button.ts

@@ -9,7 +9,7 @@ import { getBackend } from "../backends/index";
 declare global {
   namespace JSX {
     interface IntrinsicElements {
-      BUTTON: React.PropsWithChildren<Props>
+      BUTTON: React.PropsWithChildren<Props>;
     }
   }
 }
@@ -28,7 +28,7 @@ export default (p: Props) => {
   };
   const defaultProps = {
     style: {},
-    onPress: () => { },
+    onPress: () => {},
     title: "Button"
   };
 
@@ -52,6 +52,11 @@ export default (p: Props) => {
 
   const containerProps = Container(
     child => {
+      if (child.type === "text")
+        throw new Error(
+          "Button takes no children. If you are trying to set the title, use the title prop."
+        );
+
       child.element.setParent(element);
       if (child.node) {
         yogaProps.node.insertChild(child.node, yogaProps.node.getChildCount());

src/components/Image.ts

@@ -30,7 +30,7 @@ interface ImageStyle extends React.CSSProperties {
 declare global {
   namespace JSX {
     interface IntrinsicElements {
-      IMAGE: Props
+      IMAGE: Props;
     }
   }
 }
@@ -124,6 +124,8 @@ export default (p: Props) => {
       style: (style: ImageStyle) => {
         if (style.resizeMode) {
           resizeMode.r = style.resizeMode;
+        } else {
+          resizeMode.r = "cover";
         }
         element.setStyleSheet(style);
         yogaProps.applyYogaStyle(style);

src/components/Root.ts

@@ -1,7 +1,7 @@
 import propChecker from "../utils/propChecker";
 import { disconnectDevtools } from "../devtools";
 import { Container } from "./Container";
-import { getBackend } from '../backends/index'
+import { getBackend } from "../backends/index";
 import { Component } from "./Base";
 
 export interface Root {
@@ -13,14 +13,14 @@ export default (props: {}) => {
   const propTypes = {};
   const defaultProps = {};
 
-  const AppElement = getBackend()["AppElement"]
+  const AppElement = getBackend()["AppElement"];
   const element = new AppElement();
 
   props = propChecker(props, propTypes, defaultProps, "Root");
 
   const containerProps = Container(
-    () => { },
-    () => { }
+    () => {},
+    () => {}
   );
 
   const quit = () => {
@@ -35,7 +35,13 @@ export default (props: {}) => {
   const interval = setInterval(() => {
     if (containerProps.children && containerProps.children.length) {
       for (let i = 0; i < containerProps.children[0].children.length; i++) {
-        const closed = containerProps.children[0].children[i].element.getClosed();
+        if (!containerProps.children[0].children[i].element.getClosed)
+          throw new Error(
+            "Could not find Window or App. Did you forget to define one?"
+          );
+        const closed = containerProps.children[0].children[
+          i
+        ].element.getClosed();
         if (!closed) {
           element.runLoop();
           return;