Update to TypeScript 3.7 (#3275)

and update to prettier 1.19

Also, update `assert()` and remove not null assertions where possibly
in `cli`.

Closes #3273

1 files changed, 3 insertions, 5 deletions

diff --git a/cli/js/workers.ts b/cli/js/workers.ts
index 028817573..9d46ace22 100644
--- a/cli/js/workers.ts
+++ b/cli/js/workers.ts
@@ -160,11 +160,9 @@ export class WorkerImpl implements Worker {
     );
     this.run();
     this.isClosedPromise = hostGetWorkerClosed(this.id);
-    this.isClosedPromise.then(
-      (): void => {
-        this.isClosing = true;
-      }
-    );
+    this.isClosedPromise.then((): void => {
+      this.isClosing = true;
+    });
   }
 
   get closed(): Promise<void> {