DARKNET: Darkweb Expansion Project & Bitnode (#2139)

This is BN15. It is a really big change; see the PR for all the details.

src/utils/TypeAssertion.ts

@@ -100,3 +100,23 @@ export function assertSaveData(unknownData: unknown): asserts unknownData is Sav
     throw new Error("Invalid save data. It's Uint8Array, but its buffer is not ArrayBuffer.");
   }
 }
+
+/**
+ * This function only narrows down the type to "number" at compile time, but it guarantees the value is a finite number
+ * at runtime.
+ */
+export function assertFiniteNumber(v: unknown): asserts v is number {
+  if (!Number.isFinite(v)) {
+    console.error("The value is not a finite number. Value:", v);
+    const type = getFriendlyType(v);
+    throw new TypeAssertionError(`The value is not a finite number. Its type is ${type}.`, type);
+  }
+}
+
+export function assertNonNullish<T>(v: unknown): asserts v is NonNullable<T> {
+  if (v === null || v === undefined) {
+    console.error("The value is nullish. Value:", v);
+    const type = getFriendlyType(v);
+    throw new TypeAssertionError(`The value is nullish. Its type is ${type}.`, type);
+  }
+}