Upgrade typescript

packages/dataverse/src/dataverse.test.ts

@@ -696,7 +696,7 @@ describe(`The exhaustive guide to dataverse`, () => {
 
       // Let's create a function that will set a property of an object by a pointer, similar to `lodash.set()`.
       // The function will take the root object, the pointer, and the new value.
-      function setByPointer<Root, Value>(
+      function setByPointer<Root extends {}, Value>(
         root: Root,
         getPointer: (ptr: Pointer<Root>) => Pointer<Value>,
         newValue: Value,

packages/dataverse/src/prism/prism.ts

@@ -233,7 +233,7 @@ class PrismInstance<V> implements Prism<V> {
     }
 
     // let's cache the last value so we don't call the listener if the value hasn't changed
-    let lastValue =
+    let lastValue: V | typeof emptyObject =
       // use an empty object as the initial value so that the listener is called on the first tick.
       // if we were to use, say, undefined, and this.getValue() also returned undefined, the listener
       // would never be called.