feat(async): stabilize Lazy

async/deno.json

@@ -20,7 +20,7 @@
     "./unstable-wait-for": "./unstable_wait_for.ts",
     "./unstable-semaphore": "./unstable_semaphore.ts",
     "./unstable-circuit-breaker": "./unstable_circuit_breaker.ts",
-    "./unstable-lazy": "./unstable_lazy.ts",
+    "./lazy": "./lazy.ts",
     "./unstable-pool-settled": "./unstable_pool_settled.ts",
     "./unstable-channel": "./unstable_channel.ts"
   }

async/unstable_lazy.ts → async/lazy.ts

@@ -3,8 +3,6 @@
 
 /**
  * Options for {@linkcode Lazy.prototype.get}.
- *
- * @experimental **UNSTABLE**: New API, yet to be vetted.
  */
 export interface LazyGetOptions {
   /**
@@ -31,7 +29,7 @@ export interface LazyGetOptions {
  * @example Concurrent deduplication
  *
  * ```ts
- * import { Lazy } from "@std/async/unstable-lazy";
+ * import { Lazy } from "@std/async/lazy";
  * import { assertEquals } from "@std/assert";
  *
  * let initCount = 0;
@@ -49,7 +47,7 @@ export interface LazyGetOptions {
  * @example Composing with retry
  *
  * ```ts ignore
- * import { Lazy } from "@std/async/unstable-lazy";
+ * import { Lazy } from "@std/async/lazy";
  * import { retry } from "@std/async/retry";
  *
  * const db = new Lazy(() =>
@@ -58,8 +56,6 @@ export interface LazyGetOptions {
  * await db.get();
  * ```
  *
- * @experimental **UNSTABLE**: New API, yet to be vetted.
- *
  * @typeParam T The type of the lazily initialized value.
  */
 export class Lazy<T> {
@@ -71,8 +67,6 @@ export class Lazy<T> {
   /**
    * Creates a new lazy value.
    *
-   * @experimental **UNSTABLE**: New API, yet to be vetted.
-   *
    * @param init Initializer function, called at most once (until {@linkcode reset}).
    */
   constructor(init: () => T | Promise<T>) {
@@ -88,15 +82,15 @@ export class Lazy<T> {
    *
    * @example Usage
    * ```ts no-assert
-   * import { Lazy } from "@std/async/unstable-lazy";
+   * import { Lazy } from "@std/async/lazy";
    *
    * const config = new Lazy(async () => ({ loaded: true }));
    * const value = await config.get();
    * ```
    *
    * @example Abort a slow initialization
    * ```ts
-   * import { Lazy } from "@std/async/unstable-lazy";
+   * import { Lazy } from "@std/async/lazy";
    * import { assertRejects } from "@std/assert";
    *
    * const slow = new Lazy(() => new Promise<string>(() => {}));
@@ -109,8 +103,6 @@ export class Lazy<T> {
    * );
    * ```
    *
-   * @experimental **UNSTABLE**: New API, yet to be vetted.
-   *
    * @param options Optional settings for this call.
    * @returns The cached or newly initialized value.
    */
@@ -163,7 +155,7 @@ export class Lazy<T> {
    *
    * @example Check initialization state
    * ```ts
-   * import { Lazy } from "@std/async/unstable-lazy";
+   * import { Lazy } from "@std/async/lazy";
    * import { assertEquals } from "@std/assert";
    *
    * const lazy = new Lazy(() => 42);
@@ -172,8 +164,6 @@ export class Lazy<T> {
    * assertEquals(lazy.initialized, true);
    * ```
    *
-   * @experimental **UNSTABLE**: New API, yet to be vetted.
-   *
    * @returns `true` if the value has been initialized, `false` otherwise.
    */
   get initialized(): boolean {
@@ -187,7 +177,7 @@ export class Lazy<T> {
    *
    * @example Fast-path when already initialized
    * ```ts
-   * import { Lazy } from "@std/async/unstable-lazy";
+   * import { Lazy } from "@std/async/lazy";
    * import { assertEquals } from "@std/assert";
    *
    * const config = new Lazy(async () => ({ port: 8080 }));
@@ -199,15 +189,13 @@ export class Lazy<T> {
    *
    * @example Not yet initialized
    * ```ts
-   * import { Lazy } from "@std/async/unstable-lazy";
+   * import { Lazy } from "@std/async/lazy";
    * import { assertEquals } from "@std/assert";
    *
    * const lazy = new Lazy(() => 42);
    * assertEquals(lazy.peek(), { ok: false });
    * ```
    *
-   * @experimental **UNSTABLE**: New API, yet to be vetted.
-   *
    * @returns `{ ok: true, value }` if the value has been initialized, or
    *   `{ ok: false }` if not yet initialized or still in-flight.
    */
@@ -224,15 +212,13 @@ export class Lazy<T> {
    *
    * @example Force reload
    * ```ts ignore
-   * import { Lazy } from "@std/async/unstable-lazy";
+   * import { Lazy } from "@std/async/lazy";
    *
    * const config = new Lazy(async () => loadConfig());
    * await config.get();
    * config.reset();
    * const fresh = await config.get();
    * ```
-   *
-   * @experimental **UNSTABLE**: New API, yet to be vetted.
    */
   reset(): void {
     this.#promise = undefined;

async/unstable_lazy_test.ts → async/lazy_test.ts

@@ -1,7 +1,7 @@
 // Copyright 2018-2026 the Deno authors. MIT license.
 
 import { assertEquals, assertRejects, assertStrictEquals } from "@std/assert";
-import { Lazy } from "./unstable_lazy.ts";
+import { Lazy } from "./lazy.ts";
 
 Deno.test("Lazy.get() initializes and returns sync value", async () => {
   const lazy = new Lazy(() => 42);
@@ -181,6 +181,35 @@ Deno.test("Lazy.reset() does not affect in-flight initialization", async () => {
   assertEquals(value, "ok");
 });
 
+Deno.test("Lazy.get() after reset() during in-flight triggers fresh init", async () => {
+  let initCount = 0;
+  const holders: { resolve: (v: number) => void }[] = [];
+  const lazy = new Lazy<number>(
+    () =>
+      new Promise((res) => {
+        initCount++;
+        holders.push({ resolve: res });
+      }),
+  );
+
+  const first = lazy.get();
+  await Promise.resolve();
+  assertEquals(initCount, 1);
+
+  lazy.reset();
+  const second = lazy.get();
+  await Promise.resolve();
+  assertEquals(initCount, 2);
+
+  holders[0]!.resolve(1);
+  holders[1]!.resolve(2);
+
+  assertEquals(await first, 1);
+  assertEquals(await second, 2);
+  assertEquals(lazy.initialized, true);
+  assertEquals(lazy.peek(), { ok: true, value: 2 });
+});
+
 Deno.test("Lazy.get() resolves falsy values correctly", async (t) => {
   await t.step("0", async () => {
     const lazy = new Lazy(() => 0);

async/mod.ts

@@ -25,3 +25,4 @@ export * from "./pool.ts";
 export * from "./tee.ts";
 export * from "./retry.ts";
 export * from "./all_keyed.ts";
+export * from "./lazy.ts";