From bacf9cf38388c32244768845b347dfb907dcd419 Mon Sep 17 00:00:00 2001
From: memdmp <memdmp@estrogen.zone>
Date: Thu, 14 Aug 2025 14:29:38 +0200
Subject: feat: an implementation of OnceCell

---
 src/lib/vendor/once-cell/index.ts | 94 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 94 insertions(+)
 create mode 100644 src/lib/vendor/once-cell/index.ts

(limited to 'src/lib')

diff --git a/src/lib/vendor/once-cell/index.ts b/src/lib/vendor/once-cell/index.ts
new file mode 100644
index 0000000..5ae37f0
--- /dev/null
+++ b/src/lib/vendor/once-cell/index.ts
@@ -0,0 +1,94 @@
+export type Proxy<T> = T;
+export type OnceCell<T> = Proxy<T & {
+  /**
+   * Do not use.
+   * @deprecated Implementation Detail.
+   * @internal @private @ignore
+   */
+  '*internal.oncecelldereference': T
+}>;
+export type OnceCellConstructor = Proxy<(<T>(create: () => T) => Proxy<T>) & (new <T>(create: () => T) => OnceCell<T>) & {
+  dereference: <T>(cell: OnceCell<T>) => T
+}>;
+/**
+ * @license MIT
+ * @copyright memdmp <memdmp@estrogen.zone>
+ */
+export const OnceCell = new Proxy(
+  // We use the function keyword here to indicate that this *may* be a constructor
+  function <T>(create: () => T): OnceCell<T> {
+    if (typeof create !== 'function') throw new Error('Must pass function to OnceCell')
+    let createOnce = (): T extends object ? T : never => {
+      const t = create();
+      return (createOnce = () => t as T extends object ? T : never)()
+    }
+    const onceCellProxyImplementation: ProxyHandler<{
+      get value(): T
+    }> = {
+      get(_, idx, receiver) {
+        const target = createOnce();
+        if (idx === '*internal.oncecelldereference') return target;
+        // .valueOf() and similar prototype methods should be proxied properly
+        if (!Object.hasOwnProperty.call(target, idx) && typeof target[idx as keyof T] === 'function') {
+          return (...args: unknown[]) => {
+            // @ts-expect-error we don't know .call's argument types, so we just hope and pray they're good and leave it to the caller to deal with it if it isn't
+            return target[idx as keyof T].call(target, args);
+          }
+        }
+        // return Reflect.get(obj, idx, receiver)
+        return target[idx as keyof T];
+      },
+      set(_, ...args) {
+        return Reflect.set(createOnce(), ...args)
+      },
+      has(_, idx, ...args) {
+        if (idx === '*internal.oncecelldereference') return true // to comply with the OnceCell type declaration's meaning
+        return Reflect.has(createOnce(), idx, ...args)
+      },
+      deleteProperty(_, ...args) {
+        return Reflect.deleteProperty(createOnce(), ...args)
+      },
+      isExtensible(_, ...args) {
+        return Reflect.isExtensible(createOnce(), ...args)
+      },
+      ownKeys(_, ...args) {
+        return Reflect.ownKeys(createOnce(), ...args)
+      },
+      defineProperty(_, ...args) {
+        return Reflect.defineProperty(createOnce(), ...args)
+      },
+      getOwnPropertyDescriptor(_, ...args) {
+        return Reflect.getOwnPropertyDescriptor(createOnce(), ...args)
+      },
+      preventExtensions(_, ...args) {
+        return Reflect.preventExtensions(createOnce(), ...args)
+      },
+      getPrototypeOf(_, ...args) {
+        return Reflect.getPrototypeOf(createOnce(), ...args)
+      },
+      setPrototypeOf(_, ...args) {
+        return Reflect.setPrototypeOf(createOnce(), ...args)
+      },
+      apply(_, ...args) {
+        type F = (this: any, ...args: any[]) => any
+        return Reflect.apply(createOnce() as unknown as T extends F ? F : never, ...args)
+      },
+      construct(_, ...args) {
+        type F = (this: any, ...args: any[]) => any
+        return Reflect.construct(createOnce() as unknown as T extends F ? F : never, ...args)
+      },
+    }
+    return new Proxy({
+      /** For debuggers */
+      get value() {
+        return createOnce()
+      }
+    }, onceCellProxyImplementation) as unknown as OnceCell<T>
+  }, {
+  construct(onceCellCreationFunction, argArray, newTarget) {
+    return onceCellCreationFunction(argArray[0])
+  },
+}) as OnceCellConstructor
+OnceCell.dereference = (t) => Reflect.get(t as object, '*internal.oncecelldereference', t)
+Object.freeze(OnceCell)
+export default OnceCell
-- 
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