fix(ext/kv): KvU64#valueOf and KvU64 inspect (#18656)

`new Deno.KvU64(1n) + 2n == 3n` is now true.

`new Deno.KvU64(1n)` is now inspected as `[Deno.KvU64: 1n]`
(`Object(1n)` is inspected as `[BigInt: 1n]`).

---------

Co-authored-by: Bartek Iwańczuk <biwanczuk@gmail.com>

cli/tests/unit/kv_test.ts

@@ -578,19 +578,31 @@ Deno.test("KvU64 underflow", () => {
   }, RangeError);
 });
 
-Deno.test("KvU64 frozen", () => {
-  const a = new Deno.KvU64(1n);
-  assertThrows(() => {
-    // @ts-expect-error value is readonly
-    a.value = 2n;
-  }, TypeError);
-});
-
 Deno.test("KvU64 unbox", () => {
   const a = new Deno.KvU64(1n);
   assertEquals(a.value, 1n);
 });
 
+Deno.test("KvU64 unbox with valueOf", () => {
+  const a = new Deno.KvU64(1n);
+  assertEquals(a.valueOf(), 1n);
+});
+
+Deno.test("KvU64 auto-unbox", () => {
+  const a = new Deno.KvU64(1n);
+  assertEquals(a as unknown as bigint + 1n, 2n);
+});
+
+Deno.test("KvU64 toString", () => {
+  const a = new Deno.KvU64(1n);
+  assertEquals(a.toString(), "1");
+});
+
+Deno.test("KvU64 inspect", () => {
+  const a = new Deno.KvU64(1n);
+  assertEquals(Deno.inspect(a), "[Deno.KvU64: 1n]");
+});
+
 async function collect<T>(
   iter: Deno.KvListIterator<T>,
 ): Promise<Deno.KvEntry<T>[]> {

ext/kv/01_db.ts

@@ -2,8 +2,15 @@
 
 // @ts-ignore internal api
 const {
-  ObjectGetPrototypeOf,
   AsyncGeneratorPrototype,
+  BigIntPrototypeToString,
+  ObjectFreeze,
+  ObjectGetPrototypeOf,
+  ObjectPrototypeIsPrototypeOf,
+  StringPrototypeReplace,
+  SymbolFor,
+  SymbolToStringTag,
+  Uint8ArrayPrototype,
 } = globalThis.__bootstrap.primordials;
 const core = Deno.core;
 const ops = core.ops;
@@ -289,7 +296,7 @@ const MIN_U64 = BigInt("0");
 const MAX_U64 = BigInt("0xffffffffffffffff");
 
 class KvU64 {
-  readonly value: bigint;
+  value: bigint;
 
   constructor(value: bigint) {
     if (typeof value !== "bigint") {
@@ -299,11 +306,31 @@ class KvU64 {
       throw new RangeError("value must be a positive bigint");
     }
     if (value > MAX_U64) {
-      throw new RangeError("value must be a 64-bit unsigned integer");
+      throw new RangeError("value must fit in a 64-bit unsigned integer");
     }
     this.value = value;
     Object.freeze(this);
   }
+
+  valueOf() {
+    return this.value;
+  }
+
+  toString() {
+    return BigIntPrototypeToString(this.value);
+  }
+
+  get [SymbolToStringTag]() {
+    return "Deno.KvU64";
+  }
+
+  [SymbolFor("Deno.privateCustomInspect")](inspect, inspectOptions) {
+    return StringPrototypeReplace(
+      inspect(Object(this.value), inspectOptions),
+      "BigInt",
+      "Deno.KvU64",
+    );
+  }
 }
 
 function deserializeValue(entry: RawKvEntry): Deno.KvEntry<unknown> {
@@ -330,15 +357,15 @@ function deserializeValue(entry: RawKvEntry): Deno.KvEntry<unknown> {
 }
 
 function serializeValue(value: unknown): RawValue {
-  if (value instanceof Uint8Array) {
+  if (ObjectPrototypeIsPrototypeOf(Uint8ArrayPrototype, value)) {
     return {
       kind: "bytes",
       value,
     };
-  } else if (value instanceof KvU64) {
+  } else if (ObjectPrototypeIsPrototypeOf(KvU64.prototype, value)) {
     return {
       kind: "u64",
-      value: value.value,
+      value: value.valueOf(),
     };
   } else {
     return {
@@ -398,13 +425,13 @@ class KvListIterator extends AsyncIterator
     let start: Deno.KvKey | undefined;
     let end: Deno.KvKey | undefined;
     if ("prefix" in selector && selector.prefix !== undefined) {
-      prefix = Object.freeze([...selector.prefix]);
+      prefix = ObjectFreeze([...selector.prefix]);
     }
     if ("start" in selector && selector.start !== undefined) {
-      start = Object.freeze([...selector.start]);
+      start = ObjectFreeze([...selector.start]);
     }
     if ("end" in selector && selector.end !== undefined) {
-      end = Object.freeze([...selector.end]);
+      end = ObjectFreeze([...selector.end]);
     }
     if (prefix) {
       if (start && end) {

ext/kv/lib.rs

@@ -53,8 +53,7 @@ impl UnstableChecker {
 }
 
 deno_core::extension!(deno_kv,
-  // TODO(bartlomieju): specify deps
-  deps = [ ],
+  deps = [ deno_console ],
   parameters = [ DBH: DatabaseHandler ],
   ops = [
     op_kv_database_open<DBH>,