Files
yafff/lib/store.ts
Morten Olsen 0ab9a27493 init
2025-09-21 08:52:42 +02:00

113 lines
3.2 KiB
TypeScript

type StoreOptions<TState extends Record<string, unknown> = Record<string, unknown>> = {
setup: () => TState;
};
const globalScope = new Map<unknown, unknown>();
const getSymbol = Symbol('getValue');
const storeSymbol = Symbol('htmlStore');
const undefinedSymbol = Symbol('undefinedValue');
const proxyObject = <T extends Record<string, unknown>>(init: T) => {
const emitter = new EventTarget();
const wrap = <T extends Record<string | number | symbol, unknown>>(obj: T) =>
new Proxy(obj, {
get: (target, prop) => {
if (prop === getSymbol) {
return target;
}
const value = target[prop];
if (!value || typeof value !== 'object') {
return Object.assign(value ?? undefinedSymbol, {
[getSymbol]: () => target[prop],
});
}
return wrap(value as Record<string, unknown>);
},
set: (target: Record<string | number | symbol, unknown>, prop, value) => {
target[prop] = value;
emitter.dispatchEvent(new Event('change'));
return true;
},
});
const state = wrap(init);
return { state, emitter };
};
const store = <TState extends Record<string, unknown>>(options: StoreOptions<TState>) => {
const create = () => {
const emitter = new EventTarget();
const stateProxy = proxyObject(options.setup());
stateProxy.emitter.addEventListener('change', () => {
emitter.dispatchEvent(new Event('change'));
});
return {
emitter,
state: stateProxy.state,
};
};
const get = (elm?: HTMLElement) => {
while (elm) {
if (storeSymbol in elm) {
const localStore = elm[storeSymbol] as Map<unknown, unknown>;
if (!localStore.has(this)) {
continue;
}
return localStore.get(this) as ReturnType<typeof create>;
}
elm = elm.parentElement || undefined;
}
if (!globalScope.has(this)) {
globalScope.set(this, create());
}
return globalScope.get(this) as ReturnType<typeof create>;
};
return {
create,
get,
};
};
type Store<TState extends Record<string, unknown> = Record<string, unknown>> = ReturnType<typeof store<TState>>;
const htmlElementContext = (htmlElement: HTMLElement) => {
const emitter = new EventTarget();
return {
emitter,
get: <TStore extends Store>(store: TStore) => {
const context = store.get(htmlElement);
context.emitter.addEventListener('change', () => {
emitter.dispatchEvent(new Event('change'));
});
return context.state;
},
};
};
type HtmlElementContext = ReturnType<typeof htmlElementContext>;
const value = <T>(init: T) =>
store({
setup: () => ({ value: init }),
});
function getWithStore<T>(value: T) {
if (value && value !== null && typeof value === 'object' && getSymbol in value) {
return (value[getSymbol] as () => unknown)();
}
return value;
}
const expandTemplateStringFromStore = <T = unknown>(strings: TemplateStringsArray, ...values: T[]) => {
return strings.flatMap((current, i) => {
return [current, getWithStore(values[i]) ?? ''];
});
};
export type { HtmlElementContext, Store };
export { store, value, htmlElementContext, getWithStore, expandTemplateStringFromStore, storeSymbol };