@syncedstore/core/src/object.ts

SyncedStore is an easy-to-use library for building collaborative applications that sync automatically. It's built on top of Yjs, a proven, high performance CRDT implementation.

import { $reactive, $reactiveproxy } from "@reactivedata/reactive";
import * as Y from "yjs";
import { getYjsValue, INTERNAL_SYMBOL } from ".";
import { CRDTArray } from "./array";
import { Box } from "./boxed";
import { crdtValue, parseYjsReturnValue, yToWrappedCache, ObjectSchemaType } from "./internal";

export type CRDTObject<T extends ObjectSchemaType> = {
  [P in keyof T]?: T[P] extends Box<infer A>
    ? Box<A>
    : T[P] extends Array<infer A>
    ? CRDTArray<A>
    : T[P] extends ObjectSchemaType
    ? CRDTObject<T[P]>
    : T[P];
} & {
  [INTERNAL_SYMBOL]?: Y.Map<T>;
};

export function crdtObject<T extends ObjectSchemaType>(initializer: T, map = new Y.Map<any>()) {
  if (map[$reactive]) {
    throw new Error("unexpected");
    // map = map[$reactive].raw;
  }

  const proxy = new Proxy({} as any as CRDTObject<T>, {
    set: (target, p, value) => {
      if (typeof p !== "string") {
        throw new Error();
      }
      const wrapped = crdtValue(value); // TODO: maybe set cache
      let valueToSet = getYjsValue(wrapped) || wrapped;

      if (valueToSet instanceof Box) {
        valueToSet = valueToSet.value;
      }

      if (valueToSet instanceof Y.AbstractType && valueToSet.parent) {
        throw new Error("Not supported: reassigning object that already occurs in the tree.");
      }

      map.set(p, valueToSet);

      return true;
    },
    get: (target, p, receiver) => {
      if (p === INTERNAL_SYMBOL) {
        return map;
      }
      if (typeof p !== "string") {
        return Reflect.get(target, p);
        // throw new Error("get non string parameter");
      }
      let ic: any;
      if (receiver && receiver[$reactiveproxy]) {
        ic = receiver[$reactiveproxy]?.implicitObserver;
        (map as any)._implicitObserver = ic;
      } else {
        // console.warn("no receiver getting property", p);
      }
      let ret = map.get(p);
      ret = parseYjsReturnValue(ret, ic);
      return ret;
    },
    deleteProperty: (target, p) => {
      if (typeof p !== "string") {
        throw new Error();
      }
      if (map.has(p)) {
        map.delete(p);
        return true;
      } else {
        return false;
      }
    },
    has: (target, p) => {
      if (typeof p === "string" && map.has(p)) {
        return true;
      }
      return false;
    },
    getOwnPropertyDescriptor(target, p) {
      if (typeof p === "string" && map.has(p)) {
        return {
          enumerable: true,
          configurable: true,
        };
      }
      return undefined;
    },
    ownKeys: (target) => {
      return Array.from(map.keys());
    },
  });

  yToWrappedCache.set(map, proxy);

  for (let key in initializer) {
    proxy[key] = initializer[key] as any;
  }

  return proxy;
}