Improve proxyLazy
This commit is contained in:
parent
9663e229a6
commit
440baf6028
|
@ -16,9 +16,46 @@
|
|||
* along with this program. If not, see <https://www.gnu.org/licenses/>.
|
||||
*/
|
||||
|
||||
import { makeLazy } from "./misc";
|
||||
// Proxies demand that these properties be unmodified, so proxyLazy
|
||||
// will always return the function default for them.
|
||||
const unconfigurable = ["arguments", "caller", "prototype"];
|
||||
|
||||
const ProxyDummy = function () { };
|
||||
const handler: ProxyHandler<any> = {};
|
||||
|
||||
for (const method of [
|
||||
"apply",
|
||||
"construct",
|
||||
"defineProperty",
|
||||
"deleteProperty",
|
||||
"get",
|
||||
"getOwnPropertyDescriptor",
|
||||
"getPrototypeOf",
|
||||
"has",
|
||||
"isExtensible",
|
||||
"ownKeys",
|
||||
"preventExtensions",
|
||||
"set",
|
||||
"setPrototypeOf"
|
||||
]) {
|
||||
handler[method] =
|
||||
(target: any, ...args: any[]) => Reflect[method](target.get(), ...args);
|
||||
}
|
||||
|
||||
handler.ownKeys = target => {
|
||||
const v = target.get();
|
||||
const keys = Reflect.ownKeys(v);
|
||||
for (const key of unconfigurable) {
|
||||
if (!keys.includes(key)) keys.push(key);
|
||||
}
|
||||
return keys;
|
||||
};
|
||||
|
||||
handler.getOwnPropertyDescriptor = (target, p) => {
|
||||
if (typeof p === "string" && unconfigurable.includes(p))
|
||||
return Reflect.getOwnPropertyDescriptor(target, p);
|
||||
|
||||
return Reflect.getOwnPropertyDescriptor(target.get(), p);
|
||||
};
|
||||
|
||||
/**
|
||||
* Wraps the result of {@see makeLazy} in a Proxy you can consume as if it wasn't lazy.
|
||||
|
@ -30,17 +67,10 @@ const ProxyDummy = function () { };
|
|||
* @example const mod = proxyLazy(() => findByProps("blah")); console.log(mod.blah);
|
||||
*/
|
||||
export function proxyLazy<T>(factory: () => T): T {
|
||||
const lazy = makeLazy(factory);
|
||||
const proxyDummy: { (): void; cachedValue?: T; get(): T; } = function () { };
|
||||
|
||||
return new Proxy(ProxyDummy, {
|
||||
get: (_, prop) => lazy()[prop],
|
||||
set: (_, prop, value) => lazy()[prop] = value,
|
||||
has: (_, prop) => prop in lazy(),
|
||||
apply: (_, $this, args) => (lazy() as Function).apply($this, args),
|
||||
ownKeys: () => Reflect.ownKeys(lazy() as object),
|
||||
construct: (_, args) => Reflect.construct(lazy() as Function, args),
|
||||
deleteProperty: (_, prop) => delete lazy()[prop],
|
||||
defineProperty: (_, property, attributes) => !!Object.defineProperty(lazy(), property, attributes),
|
||||
getPrototypeOf: () => Object.getPrototypeOf(lazy())
|
||||
}) as any as T;
|
||||
proxyDummy.cachedValue = void 0;
|
||||
proxyDummy.get = () => proxyDummy.cachedValue ??= factory();
|
||||
|
||||
return new Proxy(proxyDummy, handler) as any;
|
||||
}
|
||||
|
|
Loading…
Reference in a new issue