tinybase/persisters/persister-remote/index.js

A reactive data store and sync engine.

const EMPTY_STRING = '';

const THOUSAND = 1e3;
const startInterval = (callback, sec, immediate) => {
  return setInterval(callback, sec * THOUSAND);
};
const stopInterval = clearInterval;
const isInstanceOf = (thing, cls) => thing instanceof cls;
const isUndefined = (thing) => thing == void 0;
const ifNotUndefined = (value, then, otherwise) =>
  isUndefined(value) ? otherwise?.() : then(value);
const isArray = (thing) => Array.isArray(thing);
const size = (arrayOrString) => arrayOrString.length;
const test = (regex, subject) => regex.test(subject);
const errorNew = (message) => {
  throw new Error(message);
};
const tryCatch = async (action, then1, then2) => {
  try {
    return await action();
  } catch (error) {
    /* istanbul ignore next */
    then1?.(error);
  }
};

const arrayForEach = (array, cb) => array.forEach(cb);
const arrayClear = (array, to) => array.splice(0, to);
const arrayPush = (array, ...values) => array.push(...values);
const arrayShift = (array) => array.shift();

const object = Object;
const getPrototypeOf = (obj) => object.getPrototypeOf(obj);
const isObject = (obj) =>
  !isUndefined(obj) &&
  ifNotUndefined(
    getPrototypeOf(obj),
    (objPrototype) =>
      objPrototype == object.prototype ||
      isUndefined(getPrototypeOf(objPrototype)),

    /* istanbul ignore next */
    () => true,
  );
const objIds = object.keys;
const objFreeze = object.freeze;
const objSize = (obj) => size(objIds(obj));
const objIsEmpty = (obj) => isObject(obj) && objSize(obj) == 0;

const jsonString = JSON.stringify;
const jsonParse = JSON.parse;
const jsonStringWithMap = (obj) =>
  jsonString(obj, (_key, value) =>
    isInstanceOf(value, Map) ? object.fromEntries([...value]) : value,
  );

const collSize = (coll) => coll?.size ?? 0;
const collHas = (coll, keyOrValue) => coll?.has(keyOrValue) ?? false;
const collIsEmpty = (coll) => isUndefined(coll) || collSize(coll) == 0;
const collForEach = (coll, cb) => coll?.forEach(cb);
const collDel = (coll, keyOrValue) => coll?.delete(keyOrValue);

const mapNew = (entries) => new Map(entries);
const mapGet = (map, key) => map?.get(key);
const mapSet = (map, key, value) =>
  isUndefined(value) ? (collDel(map, key), map) : map?.set(key, value);
const mapEnsure = (map, key, getDefaultValue, hadExistingValue) => {
  if (!collHas(map, key)) {
    mapSet(map, key, getDefaultValue());
  } else {
    hadExistingValue?.(mapGet(map, key));
  }
  return mapGet(map, key);
};
const visitTree = (node, path, ensureLeaf, pruneLeaf, p = 0) =>
  ifNotUndefined(
    (ensureLeaf ? mapEnsure : mapGet)(
      node,
      path[p],
      p > size(path) - 2 ? ensureLeaf : mapNew,
    ),
    (nodeOrLeaf) => {
      if (p > size(path) - 2) {
        if (pruneLeaf?.(nodeOrLeaf)) {
          mapSet(node, path[p]);
        }
        return nodeOrLeaf;
      }
      const leaf = visitTree(nodeOrLeaf, path, ensureLeaf, pruneLeaf, p + 1);
      if (collIsEmpty(nodeOrLeaf)) {
        mapSet(node, path[p]);
      }
      return leaf;
    },
  );

const INTEGER = /^\d+$/;
const getPoolFunctions = () => {
  const pool = [];
  let nextId = 0;
  return [
    (reuse) => (reuse ? arrayShift(pool) : null) ?? EMPTY_STRING + nextId++,
    (id) => {
      if (test(INTEGER, id) && size(pool) < 1e3) {
        arrayPush(pool, id);
      }
    },
  ];
};

const setNew = (entryOrEntries) =>
  new Set(
    isArray(entryOrEntries) || isUndefined(entryOrEntries)
      ? entryOrEntries
      : [entryOrEntries],
  );
const setAdd = (set, value) => set?.add(value);

const getWildcardedLeaves = (deepIdSet, path = [EMPTY_STRING]) => {
  const leaves = [];
  const deep = (node, p) =>
    p == size(path)
      ? arrayPush(leaves, node)
      : path[p] === null
        ? collForEach(node, (node2) => deep(node2, p + 1))
        : arrayForEach([path[p], null], (id) => deep(mapGet(node, id), p + 1));
  deep(deepIdSet, 0);
  return leaves;
};
const getListenerFunctions = (getThing) => {
  let thing;
  const [getId, releaseId] = getPoolFunctions();
  const allListeners = mapNew();
  const addListener = (
    listener,
    idSetNode,
    path,
    pathGetters = [],
    extraArgsGetter = () => [],
  ) => {
    thing ??= getThing();
    const id = getId(1);
    mapSet(allListeners, id, [
      listener,
      idSetNode,
      path,
      pathGetters,
      extraArgsGetter,
    ]);
    setAdd(visitTree(idSetNode, path ?? [EMPTY_STRING], setNew), id);
    return id;
  };
  const callListeners = (idSetNode, ids, ...extraArgs) =>
    arrayForEach(getWildcardedLeaves(idSetNode, ids), (set) =>
      collForEach(set, (id) =>
        mapGet(allListeners, id)[0](thing, ...(ids ?? []), ...extraArgs),
      ),
    );
  const delListener = (id) =>
    ifNotUndefined(mapGet(allListeners, id), ([, idSetNode, idOrNulls]) => {
      visitTree(idSetNode, idOrNulls ?? [EMPTY_STRING], void 0, (idSet) => {
        collDel(idSet, id);
        return collIsEmpty(idSet) ? 1 : 0;
      });
      mapSet(allListeners, id);
      releaseId(id);
      return idOrNulls;
    });
  const callListener = (id) =>
    ifNotUndefined(
      mapGet(allListeners, id),
      ([listener, , path = [], pathGetters, extraArgsGetter]) => {
        const callWithIds = (...ids) => {
          const index = size(ids);
          if (index == size(path)) {
            listener(thing, ...ids, ...extraArgsGetter(ids));
          } else if (isUndefined(path[index])) {
            arrayForEach(pathGetters[index]?.(...ids) ?? [], (id2) =>
              callWithIds(...ids, id2),
            );
          } else {
            callWithIds(...ids, path[index]);
          }
        };
        callWithIds();
      },
    );
  return [addListener, callListeners, delListener, callListener];
};

const scheduleRunning = mapNew();
const scheduleActions = mapNew();
const getStoreFunctions = (
  persist = 1 /* StoreOnly */,
  store,
  isSynchronizer,
) =>
  persist != 1 /* StoreOnly */ && store.isMergeable()
    ? [
        1,
        store.getMergeableContent,
        () => store.getTransactionMergeableChanges(!isSynchronizer),
        ([[changedTables], [changedValues]]) =>
          !objIsEmpty(changedTables) || !objIsEmpty(changedValues),
        store.setDefaultContent,
      ]
    : persist != 2 /* MergeableStoreOnly */
      ? [
          0,
          store.getContent,
          store.getTransactionChanges,
          ([changedTables, changedValues]) =>
            !objIsEmpty(changedTables) || !objIsEmpty(changedValues),
          store.setContent,
        ]
      : errorNew('Store type not supported by this Persister');
const createCustomPersister = (
  store,
  getPersisted,
  setPersisted,
  addPersisterListener,
  delPersisterListener,
  onIgnoredError,
  persist,
  extra = {},
  isSynchronizer = 0,
  scheduleId = [],
) => {
  let status = 0; /* Idle */
  let loads = 0;
  let saves = 0;
  let action;
  let autoLoadHandle;
  let autoSaveListenerId;
  mapEnsure(scheduleRunning, scheduleId, () => 0);
  mapEnsure(scheduleActions, scheduleId, () => []);
  const statusListeners = mapNew();
  const [
    isMergeableStore,
    getContent,
    getChanges,
    hasChanges,
    setDefaultContent,
  ] = getStoreFunctions(persist, store, isSynchronizer);
  const [addListener, callListeners, delListenerImpl] = getListenerFunctions(
    () => persister,
  );
  const setStatus = (newStatus) => {
    if (newStatus != status) {
      status = newStatus;
      callListeners(statusListeners, void 0, status);
    }
  };
  const run = async () => {
    /* istanbul ignore else */
    if (!mapGet(scheduleRunning, scheduleId)) {
      mapSet(scheduleRunning, scheduleId, 1);
      while (
        !isUndefined((action = arrayShift(mapGet(scheduleActions, scheduleId))))
      ) {
        await tryCatch(action, onIgnoredError);
      }
      mapSet(scheduleRunning, scheduleId, 0);
    }
  };
  const setContentOrChanges = (contentOrChanges) => {
    (isMergeableStore && isArray(contentOrChanges?.[0])
      ? contentOrChanges?.[2] === 1
        ? store.applyMergeableChanges
        : store.setMergeableContent
      : contentOrChanges?.[2] === 1
        ? store.applyChanges
        : store.setContent)(contentOrChanges);
  };
  const load = async (initialContent) => {
    /* istanbul ignore else */
    if (status != 2 /* Saving */) {
      setStatus(1 /* Loading */);
      loads++;
      await schedule(async () => {
        await tryCatch(
          async () => {
            const content = await getPersisted();
            if (isArray(content)) {
              setContentOrChanges(content);
            } else if (initialContent) {
              setDefaultContent(initialContent);
            } else {
              errorNew(`Content is not an array: ${content}`);
            }
          },
          () => {
            if (initialContent) {
              setDefaultContent(initialContent);
            }
          },
        );
        setStatus(0 /* Idle */);
      });
    }
    return persister;
  };
  const startAutoLoad = async (initialContent) => {
    stopAutoLoad();
    await load(initialContent);
    await tryCatch(
      async () =>
        (autoLoadHandle = await addPersisterListener(
          async (content, changes) => {
            if (changes || content) {
              /* istanbul ignore else */
              if (status != 2 /* Saving */) {
                setStatus(1 /* Loading */);
                loads++;
                setContentOrChanges(changes ?? content);
                setStatus(0 /* Idle */);
              }
            } else {
              await load();
            }
          },
        )),
      onIgnoredError,
    );
    return persister;
  };
  const stopAutoLoad = async () => {
    if (autoLoadHandle) {
      await tryCatch(
        () => delPersisterListener(autoLoadHandle),
        onIgnoredError,
      );
      autoLoadHandle = void 0;
    }
    return persister;
  };
  const isAutoLoading = () => !isUndefined(autoLoadHandle);
  const save = async (changes) => {
    /* istanbul ignore else */
    if (status != 1 /* Loading */) {
      setStatus(2 /* Saving */);
      saves++;
      await schedule(async () => {
        await tryCatch(() => setPersisted(getContent, changes), onIgnoredError);
        setStatus(0 /* Idle */);
      });
    }
    return persister;
  };
  const startAutoSave = async () => {
    stopAutoSave();
    await save();
    autoSaveListenerId = store.addDidFinishTransactionListener(() => {
      const changes = getChanges();
      if (hasChanges(changes)) {
        save(changes);
      }
    });
    return persister;
  };
  const stopAutoSave = async () => {
    if (autoSaveListenerId) {
      store.delListener(autoSaveListenerId);
      autoSaveListenerId = void 0;
    }
    return persister;
  };
  const isAutoSaving = () => !isUndefined(autoSaveListenerId);
  const startAutoPersisting = async (
    initialContent,
    startSaveFirst = false,
  ) => {
    const [call1, call2] = startSaveFirst
      ? [startAutoSave, startAutoLoad]
      : [startAutoLoad, startAutoSave];
    await call1(initialContent);
    await call2(initialContent);
    return persister;
  };
  const stopAutoPersisting = async (stopSaveFirst = false) => {
    const [call1, call2] = stopSaveFirst
      ? [stopAutoSave, stopAutoLoad]
      : [stopAutoLoad, stopAutoSave];
    await call1();
    await call2();
    return persister;
  };
  const getStatus = () => status;
  const addStatusListener = (listener) =>
    addListener(listener, statusListeners);
  const delListener = (listenerId) => {
    delListenerImpl(listenerId);
    return store;
  };
  const schedule = async (...actions) => {
    arrayPush(mapGet(scheduleActions, scheduleId), ...actions);
    await run();
    return persister;
  };
  const getStore = () => store;
  const destroy = () => {
    arrayClear(mapGet(scheduleActions, scheduleId));
    return stopAutoPersisting();
  };
  const getStats = () => ({loads, saves});
  const persister = {
    load,
    startAutoLoad,
    stopAutoLoad,
    isAutoLoading,
    save,
    startAutoSave,
    stopAutoSave,
    isAutoSaving,
    startAutoPersisting,
    stopAutoPersisting,
    getStatus,
    addStatusListener,
    delListener,
    schedule,
    getStore,
    destroy,
    getStats,
    ...extra,
  };
  return objFreeze(persister);
};

const getETag = (response) => response.headers.get('ETag');
const createRemotePersister = (
  store,
  loadUrl,
  saveUrl,
  autoLoadIntervalSeconds = 5,
  onIgnoredError,
) => {
  let lastEtag;
  const getPersisted = async () => {
    const response = await fetch(loadUrl);
    lastEtag = getETag(response);
    return jsonParse(await response.text());
  };
  const setPersisted = async (getContent) =>
    await fetch(saveUrl, {
      method: 'POST',
      headers: {'Content-Type': 'application/json'},
      body: jsonStringWithMap(getContent()),
    });
  const addPersisterListener = (listener) =>
    startInterval(async () => {
      const response = await fetch(loadUrl, {method: 'HEAD'});
      const currentEtag = getETag(response);
      if (
        !isUndefined(lastEtag) &&
        !isUndefined(currentEtag) &&
        currentEtag != lastEtag
      ) {
        lastEtag = currentEtag;
        listener();
      }
    }, autoLoadIntervalSeconds);
  const delPersisterListener = (interval) => stopInterval(interval);
  return createCustomPersister(
    store,
    getPersisted,
    setPersisted,
    addPersisterListener,
    delPersisterListener,
    onIgnoredError,
    1,
    // StoreOnly,
    {getUrls: () => [loadUrl, saveUrl]},
  );
};

export {createRemotePersister};