59 lines
1.1 KiB
JavaScript
59 lines
1.1 KiB
JavaScript
export function container(store, hash) {
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const subscribers = new Set();
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let id = hash(store);
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const containerMethods = {
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subscribe: fn => {
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subscribers.add(fn);
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return () => {
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subscribers.delete(fn);
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return subscribers.size;
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};
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},
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unsubscribeAll: () => subscribers.clear()
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};
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containerMethods._d = containerMethods.subscribe;
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function checkUpdate() {
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const newId = hash(store);
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if (id !== newId) {
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id = newId;
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subscribers.forEach(s => s(store));
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}
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}
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const p = new Proxy(store, {
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apply: (target, context, args) => {
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return target;
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},
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get: (target, name) => {
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if (name in containerMethods) {
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return containerMethods[name];
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}
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if (name === '_') {
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return target;
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}
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const thing = target[name];
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if (typeof thing === 'function') {
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return (...args) => {
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const ret = target[name](...args);
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checkUpdate();
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return ret;
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};
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}
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return thing;
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},
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set: (target, name, newVal) => {
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if (name in containerMethods) {
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throw new ReferenceError(`Cannot set ${name} in ${target}`);
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}
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target[name] = newVal;
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checkUpdate();
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return newVal;
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}
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});
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return p;
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}
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