limit-once - npm Package Compare versions

Comparing version 0.7.0 to 0.8.0

dist/esm/once-async.js

@@ -1,2 +0,1 @@
-import { bind } from "bind-event-listener";
 function onceAsync(fn) {
@@ -6,3 +5,2 @@ let state = {
   };
-  let controller = new AbortController();
   function cached(...args) {
@@ -15,7 +13,8 @@ if (state.type === "fulfilled") {
     }
+    let rejectPendingPromise;
+    function abort() {
+      rejectPendingPromise?.();
+    }
     const promise = new Promise((resolve, reject) => {
-      function listener() {
-        reject();
-      }
-      const cleanup = bind(controller.signal, { type: "abort", listener: () => reject() });
+      rejectPendingPromise = reject;
       fn.call(this, ...args).then((result) => {
@@ -30,7 +29,8 @@ state = {
         reject(...args2);
-      }).finally(cleanup);
+      });
     });
     state = {
       type: "pending",
-      promise
+      promise,
+      abort
     };
@@ -40,4 +40,5 @@ return promise;
   cached.clear = function clear() {
-    controller.abort();
-    controller = new AbortController();
+    if (state.type === "pending") {
+      state.abort();
+    }
     state = {
@@ -44,0 +45,0 @@ type: "initial"

package.json

@@ -13,3 +13,3 @@ {
   "license": "MIT",
-  "version": "0.7.0",
+  "version": "0.8.0",
   "private": false,
@@ -34,5 +34,3 @@ "repository": {
   },
-  "dependencies": {
-    "bind-event-listener": "^3.0.0"
-  },
+  "dependencies": {},
   "devDependencies": {
@@ -39,0 +37,0 @@ "@types/bun": "latest",

README.md

 # limit-once
 
-Create a `once` function that caches the result of the first function call. `limit-once` let's you lazily evaluate a value (using a function), and then hold onto the value forever.
+Gives you the ability to ensure a `function` is only called `"once"`, and that that the result of that single `function` call is returned every time.
 
@@ -10,4 +10,4 @@ > [!NOTE]
 
-- [Synchronous variant](#synchronous-variant) (`150B`)
-- [Asynchronous variant for promises](#asynchronous-variant) (`460B`)
+- [Synchronous variant](#synchronous-variant) (tiny `150B`)
+- [Asynchronous variant for promises](#asynchronous-variant) (tiny `372B`)
 - Only include the code for the variant(s) you want
@@ -33,2 +33,4 @@ - Both variants support cache clearing (avoid memory leaks)
 
+Create a new `function` that wraps an existing function, where the wrapped function is only called once.
+
 ```ts
@@ -56,2 +58,29 @@ import { once } from 'limit-once';
 
+If the function being wrapped `throw`s an error, then that `throw` is not cached, and the wrapped function is allowed to be called again
+
+```ts
+import { once } from 'limit-once';
+
+let callCount = 0;
+function maybeThrow({ shouldThrow }: { shouldThrow: boolean }): string {
+  callCount++;
+
+  if (shouldThrow) {
+    throw new Error(`Call count: ${callCount}`);
+  }
+
+  return `Call count: ${callCount}`;
+}
+const maybeThrowOnce = once(maybeThrow);
+
+expect(() => maybeThrowOnce({ shouldThrow: true })).toThrowError('Call count: 1');
+
+// failure result was not cached, underlying `maybeThrow` called again
+expect(() => maybeThrowOnce({ shouldThrow: true })).toThrowError('Call count: 2');
+
+// our first successful result will be cached
+expect(maybeThrowOnce({ shouldThrow: false })).toBe('Call count: 3');
+expect(maybeThrowOnce({ shouldThrow: false })).toBe('Call count: 3');
+```
+
 ### Cache clearing (`.clear()`)
@@ -108,3 +137,3 @@
 
-A "rejected" promise call will not be cached and will allow the wrapped function to be called again
+If the wrapped function that returns a promise has it's promise `"rejected"`, then the call will not be cached, and the underlying function can be called again.
 
@@ -179,3 +208,3 @@ ```ts
 
-If onced async function is `"pending"` when `.clear()` is called, then the promise will be rejected.
+If onced async function is `"pending"` when `.clear()` is called, then the promise(s) that the onced function has returned will be rejected.
 
@@ -192,8 +221,15 @@ ```ts
 const promise1 = getNameOnce().catch(() => {
-  console.log('rejected');
+  console.log('rejected promise 1');
 });
 
+const promise2 = getNameOnce().catch(() => {
+  console.log('rejected promise 2');
+});
+
 // cached cleared while promise was pending
 // will cause `promise1` to be rejected
 getNameOnce.clear();
+
+// console.log → "rejected promise 1"
+// console.log → "rejected promise 2"
 ```

src/once-async.ts

@@ -1,3 +0,1 @@
-import { bind } from 'bind-event-listener';
-
 type ResultValue<TFunc extends (this: any, ...args: any[]) => Promise<any>> = Awaited<
@@ -14,3 +12,3 @@ ReturnType<TFunc>
   | { type: 'initial' }
-  | { type: 'pending'; promise: Promise<T> }
+  | { type: 'pending'; promise: Promise<T>; abort: () => void }
   | { type: 'fulfilled'; result: T };
@@ -27,4 +25,2 @@
 
-  let controller = new AbortController();
-
   function cached(
@@ -45,8 +41,9 @@ this: ThisParameterType<TFunc>,
 
+    let rejectPendingPromise: (() => void) | null;
+    function abort() {
+      rejectPendingPromise?.();
+    }
+
     const promise: Promise<Result> = new Promise((resolve, reject) => {
-      function listener() {
-        reject();
-      }
-      const cleanup = bind(controller.signal, { type: 'abort', listener: () => reject() });
-
+      rejectPendingPromise = reject;
       fn.call(this, ...args)
@@ -64,7 +61,3 @@ .then((result: Result) => {
           reject(...args);
-        })
-        // this isn't needed for functionality,
-        // but it seems like a good idea to unbind the event listener
-        // to prevent possible memory leaks
-        .finally(cleanup);
+        });
     });
@@ -75,2 +68,3 @@
       promise,
+      abort,
     };
@@ -82,6 +76,6 @@
   cached.clear = function clear() {
-    controller.abort();
-    // Need to create a new controller
-    // as the old one has been aborted
-    controller = new AbortController();
+    if (state.type === 'pending') {
+      state.abort();
+    }
+
     state = {
@@ -88,0 +82,0 @@ type: 'initial',

No alert changes

Improved metrics

Total package byte prevSize

18709

increased by3.36%

Dependency count

1

decreased by-50%

Number of lines in readme file

230

increased by18.56%

Worsened metrics

Lines of code

333

decreased by-0.89%

Dependency changes

• - Removedbind-event-listener@^3.0.0

• - Removedbind-event-listener@3.0.0(transitive)