Handle reset similarly to panic. (#54)

We don't want control to continue in MicroPython.

Author: microbit-matt-hillsdon

src/board/index.ts

@@ -25,6 +25,12 @@ export class PanicError extends Error {
   }
 }
 
+export class ResetError extends Error {
+  constructor() {
+    super("reset");
+  }
+}
+
 const stoppedOpactity = "0.5";
 
 export function createBoard(notifications: Notifications, fs: FileSystem) {
@@ -323,6 +329,9 @@ export class Board {
     } catch (e: any) {
       if (e instanceof PanicError) {
         panicCode = e.code;
+      } else if (e instanceof ResetError) {
+        const noChangeRestart = () => {};
+        this.afterStopped = noChangeRestart;
       } else {
         this.notifications.onInternalError(e);
       }
@@ -370,6 +379,10 @@ export class Board {
     }
   }
 
+  /**
+   * An external reset.
+   * reset() in MicroPython code throws ResetError.
+   */
   async reset(): Promise<void> {
     const noChangeRestart = () => {};
     this.stop(noChangeRestart);
@@ -396,6 +409,10 @@ export class Board {
     throw new PanicError(code);
   }
 
+  throwReset(): void {
+    throw new ResetError();
+  }
+
   displayPanic(code: number): void {
     const sad = [
       [9, 9, 0, 9, 9],

src/jshal.js

@@ -24,7 +24,6 @@
  * THE SOFTWARE.
  */
 
-
 mergeInto(LibraryManager.library, {
   mp_js_hal_init: async function () {
     Module.board.initialize();
@@ -83,7 +82,7 @@ mergeInto(LibraryManager.library, {
   },
 
   mp_js_hal_reset: function () {
-    return Module.board.reset();
+    Module.board.throwReset();
   },
 
   mp_js_hal_panic: function (code) {
@@ -284,6 +283,9 @@ mergeInto(LibraryManager.library, {
   },
 
   mp_js_hal_log_data: function (key, value) {
-    return Module.board.dataLogging.logData(UTF8ToString(key), UTF8ToString(value));
+    return Module.board.dataLogging.logData(
+      UTF8ToString(key),
+      UTF8ToString(value)
+    );
   },
 });