@realm/react/dist/index.cjs

React specific hooks and implementation helpers for Realm

'use strict';

var Realm = require('realm');
var React = require('react');

////////////////////////////////////////////////////////////////////////////
//
// Copyright 2022 Realm Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
////////////////////////////////////////////////////////////////////////////
const numericRegEx = /^-?\d+$/;
function getCacheKey(id) {
    return `${id}`;
}
/**
 * Creates a proxy around a {@link Realm.Collection} that will create new {@link Realm.Object}
 * references on any relevant change (update, insert, deletion) and return the same
 * object reference if no changes have occurred since the last access.
 *
 * This makes the {@link Realm.Collection} behaves in an immutable way, as React expects, so
 * that a {@link Realm.Object} can be wrapped in {@link React.memo} to prevent unnecessary
 * rendering (see {@link useQuery} hook).
 * @param args {@link CachedCollectionArgs} object arguments
 * @returns Proxy object wrapping the collection
 */
function createCachedCollection({ collection, realm, updateCallback, updatedRef, objectCache = new Map(), isDerived = false, keyPaths, }) {
    const cachedCollectionHandler = {
        get: function (target, key, receiver) {
            // Pass functions through
            const value = Reflect.get(target, key, receiver);
            if (typeof value === "function") {
                if (key === "sorted" || key === "filtered") {
                    return (...args) => {
                        const col = Reflect.apply(value, target, args);
                        const { collection: newCol } = createCachedCollection({
                            collection: col,
                            realm,
                            updateCallback,
                            updatedRef,
                            objectCache,
                            isDerived: true,
                            keyPaths,
                        });
                        return newCol;
                    };
                }
                return value;
            }
            // If the key is not numeric, pass it through
            if (typeof key === "symbol" || !numericRegEx.test(key)) {
                return value;
            }
            // If the key is numeric, check if we have a cached object for this key
            const index = Number(key);
            const object = target[index];
            // If the collection is modeled in a way that objects can be null
            // then we should return null instead of undefined to stay semantically
            // correct
            if (object === null) {
                return null;
            }
            else if (typeof object === "undefined") {
                // If there is no object at this index, return undefined
                return undefined;
            }
            const objectId = object._objectKey();
            const cacheKey = getCacheKey(objectId);
            // If we do, return it...
            if (objectCache.get(cacheKey)) {
                return objectCache.get(cacheKey);
            }
            // If not then this index has either not been accessed before, or has been invalidated due
            // to a modification. Fetch it from the collection and store it in the cache
            objectCache.set(cacheKey, object);
            return object;
        },
    };
    const cachedCollectionResult = new Proxy(collection, cachedCollectionHandler);
    const listenerCallback = (listenerCollection, changes) => {
        if (changes.deletions.length > 0 || changes.insertions.length > 0 || changes.newModifications.length > 0) {
            // TODO: There is currently no way to rebuild the cache key from the changes array for deleted object.
            // Until it is possible, we clear the cache on deletions.
            // Blocking issue: https://github.com/realm/realm-core/issues/5220
            // Possible solutions:
            // a. the listenerCollection is a frozen copy of the collection before the deletion,
            // allowing accessing the _objectKey() using listenerCollection[index]._objectKey()
            // b. the callback provides an array of changed objectIds
            if (changes.deletions.length > 0) {
                objectCache.clear();
            }
            // Item(s) were modified, just clear them from the cache so that we return new instances for them
            changes.newModifications.forEach((index) => {
                const objectId = listenerCollection[index]._objectKey();
                if (objectId) {
                    const cacheKey = getCacheKey(objectId);
                    if (objectCache.has(cacheKey)) {
                        objectCache.delete(cacheKey);
                    }
                }
            });
            updatedRef.current = true;
            updateCallback();
        }
    };
    let setImmediateId = undefined;
    if (!isDerived) {
        // If we are in a transaction, then push adding the listener to the event loop.  This will allow the write transaction to finish.
        // see https://github.com/realm/realm-js/issues/4375
        if (realm.isInTransaction) {
            setImmediateId = setImmediate(() => {
                collection.addListener(listenerCallback, keyPaths);
            });
        }
        else {
            collection.addListener(listenerCallback, keyPaths);
        }
    }
    const tearDown = () => {
        if (!isDerived) {
            if (setImmediateId) {
                clearImmediate(setImmediateId);
                setImmediateId = undefined;
            }
            collection.removeListener(listenerCallback);
            objectCache.clear();
        }
    };
    return { collection: cachedCollectionResult, tearDown };
}

////////////////////////////////////////////////////////////////////////////
//
// Copyright 2022 Realm Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
////////////////////////////////////////////////////////////////////////////
/**
 * Creates a proxy around a {@link Realm.Object} that will return a new reference
 * on any relevant update to the object itself. It also wraps accesses to {@link Realm.List}
 * attributes into a {@link cachedCollection}, so that any update, insert or deletion to the
 * list will also return a new object reference.
 *
 * See {@link cachedCollection} and the `useObject` hook for description of how this
 * helps prevent unnecessary rendering.
 * @param args - {@link CachedObjectArgs} object arguments
 * @returns Proxy object wrapping the {@link Realm.Object}
 */
function createCachedObject({ object, realm, updateCallback, updatedRef, keyPaths, }) {
    const listCaches = new Map();
    const listTearDowns = [];
    // If the object doesn't exist, just return it with an noop tearDown
    //
    if (object === null) {
        return { object, tearDown: () => undefined };
    }
    // Create a cache for any Realm.List properties on the object
    for (const key of object.keys()) {
        //@ts-expect-error - TS doesn't know that the key is a valid property
        const value = object[key];
        if (value instanceof Realm.List && value.type === "object") {
            const updatedRef = { current: true };
            const { collection, tearDown } = createCachedCollection({ collection: value, realm, updateCallback, updatedRef });
            listCaches.set(key, { collection, updatedRef });
            listTearDowns.push(tearDown);
        }
    }
    // This Proxy handler intercepts any accesses into properties of the cached object
    // of type `Realm.List`, and returns a `cachedCollection` wrapping those properties
    // to allow changes in the list to trigger re-renders
    const cachedObjectHandler = {
        get: function (target, key, receiver) {
            const value = Reflect.get(target, key, receiver);
            // If its a Realm.List we need to add a proxy cache around it
            if (value instanceof Realm.List && value.type === "object") {
                if (listCaches.has(key)) {
                    // Return a new proxy wrapping the cachedCollection so that its reference gets updated,
                    // otherwise the list component will not re-render. The cachedCollection then ensures that
                    // only the modified children of the list component actually re-render.
                    const { collection, updatedRef } = listCaches.get(key);
                    if (updatedRef.current) {
                        updatedRef.current = false;
                        const proxyCollection = new Proxy(collection, {});
                        listCaches.set(key, { collection: proxyCollection, updatedRef });
                        return proxyCollection;
                    }
                    return collection;
                }
            }
            return value;
        },
    };
    const cachedObjectResult = new Proxy(object, cachedObjectHandler);
    const listenerCallback = (obj, changes) => {
        updatedRef.current = true;
        if (changes.deleted) {
            updateCallback();
        }
        else if (changes.changedProperties.length > 0) {
            // Don't force a second re-render if any of the changed properties is a Realm.List,
            // as the List's cachedCollection will force a re-render itself
            const anyListPropertyModified = changes.changedProperties.some((property) => {
                return obj[property] instanceof Realm.List && obj[property].type === "object";
            });
            const shouldRerender = !anyListPropertyModified;
            if (shouldRerender) {
                updateCallback();
            }
        }
    };
    // We cannot add a listener to an invalid object
    if (object.isValid()) {
        // If we are in a transaction, then push adding the listener to the event loop.  This will allow the write transaction to finish.
        // see https://github.com/realm/realm-js/issues/4375
        if (realm.isInTransaction) {
            setImmediate(() => {
                object.addListener(listenerCallback, keyPaths);
            });
        }
        else {
            object.addListener(listenerCallback, keyPaths);
        }
    }
    const tearDown = () => {
        object.removeListener(listenerCallback);
        for (const listTearDown of listTearDowns) {
            listTearDown();
        }
    };
    return { object: cachedObjectResult, tearDown };
}

////////////////////////////////////////////////////////////////////////////
//
// Copyright 2023 Realm Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
////////////////////////////////////////////////////////////////////////////
// Convenience function that returns the correct type for the objectForPrimaryKey function
// Since we don't have a combined declaration for this function, typescript needs to know
// which return to use based on the typeof the type argument
function getObjectForPrimaryKey(realm, type, primaryKey) {
    return typeof type === "string"
        ? realm.objectForPrimaryKey(type, primaryKey)
        : realm.objectForPrimaryKey(type, primaryKey);
}
// Convenience function that returns the correct type for the objects function
// Since we don't have a combined declaration for this function, typescript needs to know
// which return to use based on the typeof the type argument
function getObjects(realm, type) {
    return (typeof type === "string" ? realm.objects(type) : realm.objects(type));
}
function isClassModelConstructor(value) {
    return Object.getPrototypeOf(value) === Realm.Object;
}

////////////////////////////////////////////////////////////////////////////
//
// Copyright 2021 Realm Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
////////////////////////////////////////////////////////////////////////////
/**
 * Generates the `useObject` hook from a given `useRealm` hook.
 * @param useRealm - Hook that returns an open Realm instance
 * @returns useObject - Hook that is used to gain access to a single Realm object from a primary key
 */
function createUseObject(useRealm) {
    function useObject(type, primaryKey, keyPaths) {
        const realm = useRealm();
        // Create a forceRerender function for the cachedObject to use as its updateCallback, so that
        // the cachedObject can force the component using this hook to re-render when a change occurs.
        const [, forceRerender] = React.useReducer((x) => x + 1, 0);
        // Get the original object from the realm, so we can check if it exists
        const originalObject = getObjectForPrimaryKey(realm, type, primaryKey);
        // Store the primaryKey as a ref, since when it is an objectId or UUID, it will be a new instance on every render
        const primaryKeyRef = React.useRef(primaryKey);
        const collectionRef = React.useRef(getObjects(realm, type));
        const objectRef = React.useRef(null);
        const updatedRef = React.useRef(true);
        // Initializing references with a function call or class constructor will
        // cause the function or constructor to be called on ever render.
        // Even though this value is thrown away on subsequent renders, `createCachedObject` will end up registering a listener.
        // Therefore, we initialize the references with null, and only create the object if it is null
        // Ref: https://github.com/facebook/react/issues/14490
        const cachedObjectRef = React.useRef(null);
        const memoizedKeyPaths = React.useMemo(() => (typeof keyPaths === "string" ? [keyPaths] : keyPaths), 
        /* eslint-disable-next-line react-hooks/exhaustive-deps -- Memoizing the keyPaths to avoid renders */
        [JSON.stringify(keyPaths)]);
        if (!cachedObjectRef.current) {
            cachedObjectRef.current = createCachedObject({
                object: originalObject ?? null,
                realm,
                updateCallback: forceRerender,
                updatedRef,
                keyPaths: memoizedKeyPaths,
            });
        }
        // Create a ref, since the object returned from `objectForPrimaryKey` is always going to have a different reference
        const originalObjectRef = React.useRef(originalObject);
        // Wrap the cachedObject in useMemo, so we only replace it with a new instance if `primaryKey` or `type` change
        const { object, tearDown } = React.useMemo(
        // TODO: There will be an upcoming breaking change that makes objectForPrimaryKey return null
        // When this is implemented, remove `?? null`
        () => {
            // This should never happen, but if it does, we want to return a null result
            if (!cachedObjectRef.current) {
                return { object: null, tearDown: () => undefined };
            }
            // Re-instantiate the cachedObject if the primaryKey has changed or the originalObject has gone from null to not null
            if (!arePrimaryKeysIdentical(primaryKey, primaryKeyRef.current) ||
                (!originalObjectRef.current && originalObject)) {
                cachedObjectRef.current = createCachedObject({
                    object: originalObject ?? null,
                    realm,
                    updateCallback: forceRerender,
                    updatedRef,
                    keyPaths: memoizedKeyPaths,
                });
                originalObjectRef.current = originalObject;
                // Primary key has updated, so update the reference
                primaryKeyRef.current = primaryKey;
                // Signal that the object reference needs to be updated
                updatedRef.current = true;
            }
            return cachedObjectRef.current;
        }, [realm, originalObject, primaryKey, memoizedKeyPaths]);
        // Invoke the tearDown of the cachedObject when useObject is unmounted
        React.useEffect(() => {
            return tearDown;
        }, [tearDown]);
        // If the object doesn't exist, listen for insertions to the collection and force a rerender if the inserted object has the correct primary key
        React.useEffect(() => {
            const collection = collectionRef.current;
            const collectionListener = (_, changes) => {
                const primaryKeyProperty = collection?.[0]?.objectSchema()?.primaryKey;
                for (const index of changes.insertions) {
                    const object = collection[index];
                    if (primaryKeyProperty) {
                        //@ts-expect-error - if the primaryKeyProperty exists, then it is indexable. However, we don't allow it when we don't actually know the type of the object
                        const insertedPrimaryKey = object[primaryKeyProperty];
                        if (arePrimaryKeysIdentical(insertedPrimaryKey, primaryKeyRef.current)) {
                            forceRerender();
                            collection.removeListener(collectionListener);
                            break;
                        }
                    }
                }
            };
            if (!originalObjectRef.current) {
                collection.addListener(collectionListener);
            }
            return () => {
                // If the app is closing, the realm will be closed and the listener does not need to be removed if
                if (!realm.isClosed && collection) {
                    collection.removeListener(collectionListener);
                }
            };
        }, [realm, type, forceRerender]);
        // If the object has been deleted or doesn't exist for the given primary key, just return null
        if (!object?.isValid()) {
            return null;
        }
        if (updatedRef.current) {
            // Wrap object in a proxy to update the reference on rerender ( should only rerender when something has changed )
            objectRef.current = new Proxy(object, {});
            updatedRef.current = false;
        }
        // This will never be undefined, but the type system doesn't know that
        return objectRef.current;
    }
    return function useObjectOverload(typeOrOptions, primaryKey, keyPaths) {
        if (typeof typeOrOptions === "string" || isClassModelConstructor(typeOrOptions)) {
            if (typeof primaryKey === "undefined") {
                throw new Error("Expected a primary key");
            }
            /* eslint-disable-next-line react-hooks/rules-of-hooks -- We're calling `useQuery` once in any of the brances */
            return useObject(typeOrOptions, primaryKey, keyPaths);
        }
        else {
            const { type, primaryKey, keyPaths } = typeOrOptions;
            /* eslint-disable-next-line react-hooks/rules-of-hooks -- We're calling `useQuery` once in any of the brances */
            return useObject(type, primaryKey, keyPaths);
        }
    };
}
// This is a helper function that determines if two primary keys are equal.  It will also handle the case where the primary key is an ObjectId or UUID
function arePrimaryKeysIdentical(a, b) {
    if (typeof a !== typeof b) {
        return false;
    }
    if (typeof a === "string" || typeof a === "number") {
        return a === b;
    }
    if (a instanceof Realm.BSON.ObjectId && b instanceof Realm.BSON.ObjectId) {
        return a.toHexString() === b.toHexString();
    }
    if (a instanceof Realm.BSON.UUID && b instanceof Realm.BSON.UUID) {
        return a.toHexString() === b.toHexString();
    }
    return false;
}

////////////////////////////////////////////////////////////////////////////
//
// Copyright 2021 Realm Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
////////////////////////////////////////////////////////////////////////////
/**
 * Maps a value to itself
 */
function identity(value) {
    return value;
}
/**
 * Generates the `useQuery` hook from a given `useRealm` hook.
 * @param useRealm - Hook that returns an open Realm instance
 * @returns useObject - Hook that is used to gain access to a {@link Realm.Collection}
 */
function createUseQuery(useRealm) {
    function useQuery({ type, query = identity, keyPaths }, deps = []) {
        const realm = useRealm();
        // We need to add the type to the deps, so that if the type changes, the query will be re-run.
        // This will be saved in an array which will be spread into the provided deps.
        const requiredDeps = [type];
        // Create a forceRerender function for the cachedCollection to use as its updateCallback, so that
        // the cachedCollection can force the component using this hook to re-render when a change occurs.
        const [, forceRerender] = React.useReducer((x) => x + 1, 0);
        const collectionRef = React.useRef(null);
        const updatedRef = React.useRef(true);
        const queryCallbackRef = React.useRef(null);
        /* eslint-disable-next-line react-hooks/exhaustive-deps -- We want the user of this hook to be able pass in the `query` function inline (without the need to `useCallback` on it)
        This means that the query function is unstable and will be a redefined on each render of the component where `useQuery` is used
        Therefore we use the `deps` array to memoize the query function internally, and only use the returned `queryCallback` */
        const queryCallback = React.useCallback(query, [...deps, ...requiredDeps]);
        // If the query function changes, we need to update the cachedCollection
        if (queryCallbackRef.current !== queryCallback) {
            queryCallbackRef.current = queryCallback;
            updatedRef.current = true;
        }
        const queryResult = React.useMemo(() => {
            return queryCallback(getObjects(realm, type));
        }, [type, realm, queryCallback]);
        const memoizedKeyPaths = React.useMemo(() => (typeof keyPaths === "string" ? [keyPaths] : keyPaths), 
        /* eslint-disable-next-line react-hooks/exhaustive-deps -- Memoizing the keyPaths to avoid renders */
        [JSON.stringify(keyPaths)]);
        // Wrap the cachedObject in useMemo, so we only replace it with a new instance if `realm` or `queryResult` change
        const { collection, tearDown } = React.useMemo(() => {
            return createCachedCollection({
                collection: queryResult,
                realm,
                updateCallback: forceRerender,
                updatedRef,
                keyPaths: memoizedKeyPaths,
            });
        }, [realm, queryResult, memoizedKeyPaths]);
        // Invoke the tearDown of the cachedCollection when useQuery is unmounted
        React.useEffect(() => {
            return tearDown;
        }, [tearDown]);
        // This makes sure the collection has a different reference on a rerender
        // Also we are ensuring the type returned is Realm.Results, as this is known in this context
        if (updatedRef.current) {
            updatedRef.current = false;
            collectionRef.current = new Proxy(collection, {});
        }
        // This will never not be defined, but the type system doesn't know that
        return collectionRef.current;
    }
    return function useQueryOverload(typeOrOptionsOrQuery, queryOrDeps = identity, depsOrPartialOptions = []) {
        const args = { typeOrOptionsOrQuery, queryOrDeps, depsOrPartialOptions };
        /* eslint-disable react-hooks/rules-of-hooks -- We're calling `useQuery` once in any of the brances */
        if (isTypeFunctionDeps(args)) {
            return useQuery({ type: args.typeOrOptionsOrQuery, query: args.queryOrDeps }, args.depsOrPartialOptions);
        }
        if (isOptionsDepsNone(args)) {
            return useQuery(args.typeOrOptionsOrQuery, Array.isArray(args.queryOrDeps) ? args.queryOrDeps : []);
        }
        if (isFunctionDepsOptions(args)) {
            return useQuery({ ...args.depsOrPartialOptions, query: args.typeOrOptionsOrQuery }, args.queryOrDeps);
        }
        /* eslint-enable react-hooks/rules-of-hooks */
        throw new Error("Unexpected arguments passed to useQuery");
    };
}
function isTypeFunctionDeps(args) {
    const { typeOrOptionsOrQuery, queryOrDeps, depsOrPartialOptions } = args;
    return ((typeof typeOrOptionsOrQuery === "string" || isClassModelConstructor(typeOrOptionsOrQuery)) &&
        typeof queryOrDeps === "function" &&
        Array.isArray(depsOrPartialOptions));
}
function isOptionsDepsNone(args) {
    const { typeOrOptionsOrQuery, queryOrDeps } = args;
    return (typeof typeOrOptionsOrQuery === "object" &&
        typeOrOptionsOrQuery !== null &&
        (Array.isArray(queryOrDeps) || queryOrDeps === identity));
}
function isFunctionDepsOptions(args) {
    const { typeOrOptionsOrQuery, queryOrDeps, depsOrPartialOptions } = args;
    return (typeof typeOrOptionsOrQuery === "function" &&
        Array.isArray(queryOrDeps) &&
        typeof depsOrPartialOptions === "object" &&
        depsOrPartialOptions !== null);
}

////////////////////////////////////////////////////////////////////////////
//
// Copyright 2021 Realm Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
////////////////////////////////////////////////////////////////////////////
/**
 * Generates a `useRealm` hook given a RealmContext.  This allows access to the {@link Realm}
 * instance anywhere within the RealmProvider.
 * @param RealmContext - The context containing the {@link Realm} instance
 * @returns useRealm - Hook that is used to gain access to the {@link Realm} instance
 */
const createUseRealm = (RealmContext) => {
    return function useRealm() {
        // This is the context setup by `createRealmContext`
        const context = React.useContext(RealmContext);
        if (context === null) {
            throw new Error("Realm context not found.  Did you call useRealm() within a <RealmProvider/>?");
        }
        return context;
    };
};

var commonjsGlobal = typeof globalThis !== 'undefined' ? globalThis : typeof window !== 'undefined' ? window : typeof global !== 'undefined' ? global : typeof self !== 'undefined' ? self : {};

function getDefaultExportFromCjs (x) {
	return x && x.__esModule && Object.prototype.hasOwnProperty.call(x, 'default') ? x['default'] : x;
}

var lodash_isequal = {exports: {}};

/**
 * Lodash (Custom Build) <https://lodash.com/>
 * Build: `lodash modularize exports="npm" -o ./`
 * Copyright JS Foundation and other contributors <https://js.foundation/>
 * Released under MIT license <https://lodash.com/license>
 * Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
 * Copyright Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
 */
lodash_isequal.exports;

(function (module, exports) {
	/** Used as the size to enable large array optimizations. */
	var LARGE_ARRAY_SIZE = 200;

	/** Used to stand-in for `undefined` hash values. */
	var HASH_UNDEFINED = '__lodash_hash_undefined__';

	/** Used to compose bitmasks for value comparisons. */
	var COMPARE_PARTIAL_FLAG = 1,
	    COMPARE_UNORDERED_FLAG = 2;

	/** Used as references for various `Number` constants. */
	var MAX_SAFE_INTEGER = 9007199254740991;

	/** `Object#toString` result references. */
	var argsTag = '[object Arguments]',
	    arrayTag = '[object Array]',
	    asyncTag = '[object AsyncFunction]',
	    boolTag = '[object Boolean]',
	    dateTag = '[object Date]',
	    errorTag = '[object Error]',
	    funcTag = '[object Function]',
	    genTag = '[object GeneratorFunction]',
	    mapTag = '[object Map]',
	    numberTag = '[object Number]',
	    nullTag = '[object Null]',
	    objectTag = '[object Object]',
	    promiseTag = '[object Promise]',
	    proxyTag = '[object Proxy]',
	    regexpTag = '[object RegExp]',
	    setTag = '[object Set]',
	    stringTag = '[object String]',
	    symbolTag = '[object Symbol]',
	    undefinedTag = '[object Undefined]',
	    weakMapTag = '[object WeakMap]';

	var arrayBufferTag = '[object ArrayBuffer]',
	    dataViewTag = '[object DataView]',
	    float32Tag = '[object Float32Array]',
	    float64Tag = '[object Float64Array]',
	    int8Tag = '[object Int8Array]',
	    int16Tag = '[object Int16Array]',
	    int32Tag = '[object Int32Array]',
	    uint8Tag = '[object Uint8Array]',
	    uint8ClampedTag = '[object Uint8ClampedArray]',
	    uint16Tag = '[object Uint16Array]',
	    uint32Tag = '[object Uint32Array]';

	/**
	 * Used to match `RegExp`
	 * [syntax characters](http://ecma-international.org/ecma-262/7.0/#sec-patterns).
	 */
	var reRegExpChar = /[\\^$.*+?()[\]{}|]/g;

	/** Used to detect host constructors (Safari). */
	var reIsHostCtor = /^\[object .+?Constructor\]$/;

	/** Used to detect unsigned integer values. */
	var reIsUint = /^(?:0|[1-9]\d*)$/;

	/** Used to identify `toStringTag` values of typed arrays. */
	var typedArrayTags = {};
	typedArrayTags[float32Tag] = typedArrayTags[float64Tag] =
	typedArrayTags[int8Tag] = typedArrayTags[int16Tag] =
	typedArrayTags[int32Tag] = typedArrayTags[uint8Tag] =
	typedArrayTags[uint8ClampedTag] = typedArrayTags[uint16Tag] =
	typedArrayTags[uint32Tag] = true;
	typedArrayTags[argsTag] = typedArrayTags[arrayTag] =
	typedArrayTags[arrayBufferTag] = typedArrayTags[boolTag] =
	typedArrayTags[dataViewTag] = typedArrayTags[dateTag] =
	typedArrayTags[errorTag] = typedArrayTags[funcTag] =
	typedArrayTags[mapTag] = typedArrayTags[numberTag] =
	typedArrayTags[objectTag] = typedArrayTags[regexpTag] =
	typedArrayTags[setTag] = typedArrayTags[stringTag] =
	typedArrayTags[weakMapTag] = false;

	/** Detect free variable `global` from Node.js. */
	var freeGlobal = typeof commonjsGlobal == 'object' && commonjsGlobal && commonjsGlobal.Object === Object && commonjsGlobal;

	/** Detect free variable `self`. */
	var freeSelf = typeof self == 'object' && self && self.Object === Object && self;

	/** Used as a reference to the global object. */
	var root = freeGlobal || freeSelf || Function('return this')();

	/** Detect free variable `exports`. */
	var freeExports = exports && !exports.nodeType && exports;

	/** Detect free variable `module`. */
	var freeModule = freeExports && 'object' == 'object' && module && !module.nodeType && module;

	/** Detect the popular CommonJS extension `module.exports`. */
	var moduleExports = freeModule && freeModule.exports === freeExports;

	/** Detect free variable `process` from Node.js. */
	var freeProcess = moduleExports && freeGlobal.process;

	/** Used to access faster Node.js helpers. */
	var nodeUtil = (function() {
	  try {
	    return freeProcess && freeProcess.binding && freeProcess.binding('util');
	  } catch (e) {}
	}());

	/* Node.js helper references. */
	var nodeIsTypedArray = nodeUtil && nodeUtil.isTypedArray;

	/**
	 * A specialized version of `_.filter` for arrays without support for
	 * iteratee shorthands.
	 *
	 * @private
	 * @param {Array} [array] The array to iterate over.
	 * @param {Function} predicate The function invoked per iteration.
	 * @returns {Array} Returns the new filtered array.
	 */
	function arrayFilter(array, predicate) {
	  var index = -1,
	      length = array == null ? 0 : array.length,
	      resIndex = 0,
	      result = [];

	  while (++index < length) {
	    var value = array[index];
	    if (predicate(value, index, array)) {
	      result[resIndex++] = value;
	    }
	  }
	  return result;
	}

	/**
	 * Appends the elements of `values` to `array`.
	 *
	 * @private
	 * @param {Array} array The array to modify.
	 * @param {Array} values The values to append.
	 * @returns {Array} Returns `array`.
	 */
	function arrayPush(array, values) {
	  var index = -1,
	      length = values.length,
	      offset = array.length;

	  while (++index < length) {
	    array[offset + index] = values[index];
	  }
	  return array;
	}

	/**
	 * A specialized version of `_.some` for arrays without support for iteratee
	 * shorthands.
	 *
	 * @private
	 * @param {Array} [array] The array to iterate over.
	 * @param {Function} predicate The function invoked per iteration.
	 * @returns {boolean} Returns `true` if any element passes the predicate check,
	 *  else `false`.
	 */
	function arraySome(array, predicate) {
	  var index = -1,
	      length = array == null ? 0 : array.length;

	  while (++index < length) {
	    if (predicate(array[index], index, array)) {
	      return true;
	    }
	  }
	  return false;
	}

	/**
	 * The base implementation of `_.times` without support for iteratee shorthands
	 * or max array length checks.
	 *
	 * @private
	 * @param {number} n The number of times to invoke `iteratee`.
	 * @param {Function} iteratee The function invoked per iteration.
	 * @returns {Array} Returns the array of results.
	 */
	function baseTimes(n, iteratee) {
	  var index = -1,
	      result = Array(n);

	  while (++index < n) {
	    result[index] = iteratee(index);
	  }
	  return result;
	}

	/**
	 * The base implementation of `_.unary` without support for storing metadata.
	 *
	 * @private
	 * @param {Function} func The function to cap arguments for.
	 * @returns {Function} Returns the new capped function.
	 */
	function baseUnary(func) {
	  return function(value) {
	    return func(value);
	  };
	}

	/**
	 * Checks if a `cache` value for `key` exists.
	 *
	 * @private
	 * @param {Object} cache The cache to query.
	 * @param {string} key The key of the entry to check.
	 * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
	 */
	function cacheHas(cache, key) {
	  return cache.has(key);
	}

	/**
	 * Gets the value at `key` of `object`.
	 *
	 * @private
	 * @param {Object} [object] The object to query.
	 * @param {string} key The key of the property to get.
	 * @returns {*} Returns the property value.
	 */
	function getValue(object, key) {
	  return object == null ? undefined : object[key];
	}

	/**
	 * Converts `map` to its key-value pairs.
	 *
	 * @private
	 * @param {Object} map The map to convert.
	 * @returns {Array} Returns the key-value pairs.
	 */
	function mapToArray(map) {
	  var index = -1,
	      result = Array(map.size);

	  map.forEach(function(value, key) {
	    result[++index] = [key, value];
	  });
	  return result;
	}

	/**
	 * Creates a unary function that invokes `func` with its argument transformed.
	 *
	 * @private
	 * @param {Function} func The function to wrap.
	 * @param {Function} transform The argument transform.
	 * @returns {Function} Returns the new function.
	 */
	function overArg(func, transform) {
	  return function(arg) {
	    return func(transform(arg));
	  };
	}

	/**
	 * Converts `set` to an array of its values.
	 *
	 * @private
	 * @param {Object} set The set to convert.
	 * @returns {Array} Returns the values.
	 */
	function setToArray(set) {
	  var index = -1,
	      result = Array(set.size);

	  set.forEach(function(value) {
	    result[++index] = value;
	  });
	  return result;
	}

	/** Used for built-in method references. */
	var arrayProto = Array.prototype,
	    funcProto = Function.prototype,
	    objectProto = Object.prototype;

	/** Used to detect overreaching core-js shims. */
	var coreJsData = root['__core-js_shared__'];

	/** Used to resolve the decompiled source of functions. */
	var funcToString = funcProto.toString;

	/** Used to check objects for own properties. */
	var hasOwnProperty = objectProto.hasOwnProperty;

	/** Used to detect methods masquerading as native. */
	var maskSrcKey = (function() {
	  var uid = /[^.]+$/.exec(coreJsData && coreJsData.keys && coreJsData.keys.IE_PROTO || '');
	  return uid ? ('Symbol(src)_1.' + uid) : '';
	}());

	/**
	 * Used to resolve the
	 * [`toStringTag`](http://ecma-international.org/ecma-262/7.0/#sec-object.prototype.tostring)
	 * of values.
	 */
	var nativeObjectToString = objectProto.toString;

	/** Used to detect if a method is native. */
	var reIsNative = RegExp('^' +
	  funcToString.call(hasOwnProperty).replace(reRegExpChar, '\\$&')
	  .replace(/hasOwnProperty|(function).*?(?=\\\()| for .+?(?=\\\])/g, '$1.*?') + '$'
	);

	/** Built-in value references. */
	var Buffer = moduleExports ? root.Buffer : undefined,
	    Symbol = root.Symbol,
	    Uint8Array = root.Uint8Array,
	    propertyIsEnumerable = objectProto.propertyIsEnumerable,
	    splice = arrayProto.splice,
	    symToStringTag = Symbol ? Symbol.toStringTag : undefined;

	/* Built-in method references for those with the same name as other `lodash` methods. */
	var nativeGetSymbols = Object.getOwnPropertySymbols,
	    nativeIsBuffer = Buffer ? Buffer.isBuffer : undefined,
	    nativeKeys = overArg(Object.keys, Object);

	/* Built-in method references that are verified to be native. */
	var DataView = getNative(root, 'DataView'),
	    Map = getNative(root, 'Map'),
	    Promise = getNative(root, 'Promise'),
	    Set = getNative(root, 'Set'),
	    WeakMap = getNative(root, 'WeakMap'),
	    nativeCreate = getNative(Object, 'create');

	/** Used to detect maps, sets, and weakmaps. */
	var dataViewCtorString = toSource(DataView),
	    mapCtorString = toSource(Map),
	    promiseCtorString = toSource(Promise),
	    setCtorString = toSource(Set),
	    weakMapCtorString = toSource(WeakMap);

	/** Used to convert symbols to primitives and strings. */
	var symbolProto = Symbol ? Symbol.prototype : undefined,
	    symbolValueOf = symbolProto ? symbolProto.valueOf : undefined;

	/**
	 * Creates a hash object.
	 *
	 * @private
	 * @constructor
	 * @param {Array} [entries] The key-value pairs to cache.
	 */
	function Hash(entries) {
	  var index = -1,
	      length = entries == null ? 0 : entries.length;

	  this.clear();
	  while (++index < length) {
	    var entry = entries[index];
	    this.set(entry[0], entry[1]);
	  }
	}

	/**
	 * Removes all key-value entries from the hash.
	 *
	 * @private
	 * @name clear
	 * @memberOf Hash
	 */
	function hashClear() {
	  this.__data__ = nativeCreate ? nativeCreate(null) : {};
	  this.size = 0;
	}

	/**
	 * Removes `key` and its value from the hash.
	 *
	 * @private
	 * @name delete
	 * @memberOf Hash
	 * @param {Object} hash The hash to modify.
	 * @param {string} key The key of the value to remove.
	 * @returns {boolean} Returns `true` if the entry was removed, else `false`.
	 */
	function hashDelete(key) {
	  var result = this.has(key) && delete this.__data__[key];
	  this.size -= result ? 1 : 0;
	  return result;
	}

	/**
	 * Gets the hash value for `key`.
	 *
	 * @private
	 * @name get
	 * @memberOf Hash
	 * @param {string} key The key of the value to get.
	 * @returns {*} Returns the entry value.
	 */
	function hashGet(key) {
	  var data = this.__data__;
	  if (nativeCreate) {
	    var result = data[key];
	    return result === HASH_UNDEFINED ? undefined : result;
	  }
	  return hasOwnProperty.call(data, key) ? data[key] : undefined;
	}

	/**
	 * Checks if a hash value for `key` exists.
	 *
	 * @private
	 * @name has
	 * @memberOf Hash
	 * @param {string} key The key of the entry to check.
	 * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
	 */
	function hashHas(key) {
	  var data = this.__data__;
	  return nativeCreate ? (data[key] !== undefined) : hasOwnProperty.call(data, key);
	}

	/**
	 * Sets the hash `key` to `value`.
	 *
	 * @private
	 * @name set
	 * @memberOf Hash
	 * @param {string} key The key of the value to set.
	 * @param {*} value The value to set.
	 * @returns {Object} Returns the hash instance.
	 */
	function hashSet(key, value) {
	  var data = this.__data__;
	  this.size += this.has(key) ? 0 : 1;
	  data[key] = (nativeCreate && value === undefined) ? HASH_UNDEFINED : value;
	  return this;
	}

	// Add methods to `Hash`.
	Hash.prototype.clear = hashClear;
	Hash.prototype['delete'] = hashDelete;
	Hash.prototype.get = hashGet;
	Hash.prototype.has = hashHas;
	Hash.prototype.set = hashSet;

	/**
	 * Creates an list cache object.
	 *
	 * @private
	 * @constructor
	 * @param {Array} [entries] The key-value pairs to cache.
	 */
	function ListCache(entries) {
	  var index = -1,
	      length = entries == null ? 0 : entries.length;

	  this.clear();
	  while (++index < length) {
	    var entry = entries[index];
	    this.set(entry[0], entry[1]);
	  }
	}

	/**
	 * Removes all key-value entries from the list cache.
	 *
	 * @private
	 * @name clear
	 * @memberOf ListCache
	 */
	function listCacheClear() {
	  this.__data__ = [];
	  this.size = 0;
	}

	/**
	 * Removes `key` and its value from the list cache.
	 *
	 * @private
	 * @name delete
	 * @memberOf ListCache
	 * @param {string} key The key of the value to remove.
	 * @returns {boolean} Returns `true` if the entry was removed, else `false`.
	 */
	function listCacheDelete(key) {
	  var data = this.__data__,
	      index = assocIndexOf(data, key);

	  if (index < 0) {
	    return false;
	  }
	  var lastIndex = data.length - 1;
	  if (index == lastIndex) {
	    data.pop();
	  } else {
	    splice.call(data, index, 1);
	  }
	  --this.size;
	  return true;
	}

	/**
	 * Gets the list cache value for `key`.
	 *
	 * @private
	 * @name get
	 * @memberOf ListCache
	 * @param {string} key The key of the value to get.
	 * @returns {*} Returns the entry value.
	 */
	function listCacheGet(key) {
	  var data = this.__data__,
	      index = assocIndexOf(data, key);

	  return index < 0 ? undefined : data[index][1];
	}

	/**
	 * Checks if a list cache value for `key` exists.
	 *
	 * @private
	 * @name has
	 * @memberOf ListCache
	 * @param {string} key The key of the entry to check.
	 * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
	 */
	function listCacheHas(key) {
	  return assocIndexOf(this.__data__, key) > -1;
	}

	/**
	 * Sets the list cache `key` to `value`.
	 *
	 * @private
	 * @name set
	 * @memberOf ListCache
	 * @param {string} key The key of the value to set.
	 * @param {*} value The value to set.
	 * @returns {Object} Returns the list cache instance.
	 */
	function listCacheSet(key, value) {
	  var data = this.__data__,
	      index = assocIndexOf(data, key);

	  if (index < 0) {
	    ++this.size;
	    data.push([key, value]);
	  } else {
	    data[index][1] = value;
	  }
	  return this;
	}

	// Add methods to `ListCache`.
	ListCache.prototype.clear = listCacheClear;
	ListCache.prototype['delete'] = listCacheDelete;
	ListCache.prototype.get = listCacheGet;
	ListCache.prototype.has = listCacheHas;
	ListCache.prototype.set = listCacheSet;

	/**
	 * Creates a map cache object to store key-value pairs.
	 *
	 * @private
	 * @constructor
	 * @param {Array} [entries] The key-value pairs to cache.
	 */
	function MapCache(entries) {
	  var index = -1,
	      length = entries == null ? 0 : entries.length;

	  this.clear();
	  while (++index < length) {
	    var entry = entries[index];
	    this.set(entry[0], entry[1]);
	  }
	}

	/**
	 * Removes all key-value entries from the map.
	 *
	 * @private
	 * @name clear
	 * @memberOf MapCache
	 */
	function mapCacheClear() {
	  this.size = 0;
	  this.__data__ = {
	    'hash': new Hash,
	    'map': new (Map || ListCache),
	    'string': new Hash
	  };
	}

	/**
	 * Removes `key` and its value from the map.
	 *
	 * @private
	 * @name delete
	 * @memberOf MapCache
	 * @param {string} key The key of the value to remove.
	 * @returns {boolean} Returns `true` if the entry was removed, else `false`.
	 */
	function mapCacheDelete(key) {
	  var result = getMapData(this, key)['delete'](key);
	  this.size -= result ? 1 : 0;
	  return result;
	}

	/**
	 * Gets the map value for `key`.
	 *
	 * @private
	 * @name get
	 * @memberOf MapCache
	 * @param {string} key The key of the value to get.
	 * @returns {*} Returns the entry value.
	 */
	function mapCacheGet(key) {
	  return getMapData(this, key).get(key);
	}

	/**
	 * Checks if a map value for `key` exists.
	 *
	 * @private
	 * @name has
	 * @memberOf MapCache
	 * @param {string} key The key of the entry to check.
	 * @returns {boolean} Returns `true` if an entry for `key` exists, else `false`.
	 */
	function mapCacheHas(key) {
	  return getMapData(this, key).has(key);
	}

	/**
	 * Sets the map `key` to `value`.
	 *
	 * @private
	 * @name set
	 * @memberOf MapCache
	 * @param {string} key The key of the value to set.
	 * @param {*} value The value to set.
	 * @returns {Object} Returns the map cache instance.
	 */
	function mapCacheSet(key, value) {
	  var data = getMapData(this, key),
	      size = data.size;

	  data.set(key, value);
	  this.size += data.size == size ? 0 : 1;
	  return this;
	}

	// Add methods to `MapCache`.
	MapCache.prototype.clear = mapCacheClear;
	MapCache.prototype['delete'] = mapCacheDelete;
	MapCache.prototype.get = mapCacheGet;
	MapCache.prototype.has = mapCacheHas;
	MapCache.prototype.set = mapCacheSet;

	/**
	 *
	 * Creates an array cache object to store unique values.
	 *
	 * @private
	 * @constructor
	 * @param {Array} [values] The values to cache.
	 */
	function SetCache(values) {
	  var index = -1,
	      length = values == null ? 0 : values.length;

	  this.__data__ = new MapCache;
	  while (++index < length) {
	    this.add(values[index]);
	  }
	}

	/**
	 * Adds `value` to the array cache.
	 *
	 * @private
	 * @name add
	 * @memberOf SetCache
	 * @alias push
	 * @param {*} value The value to cache.
	 * @returns {Object} Returns the cache instance.
	 */
	function setCacheAdd(value) {
	  this.__data__.set(value, HASH_UNDEFINED);
	  return this;
	}

	/**
	 * Checks if `value` is in the array cache.
	 *
	 * @private
	 * @name has
	 * @memberOf SetCache
	 * @param {*} value The value to search for.
	 * @returns {number} Returns `true` if `value` is found, else `false`.
	 */
	function setCacheHas(value) {
	  return this.__data__.has(value);
	}

	// Add methods to `SetCache`.
	SetCache.prototype.add = SetCache.prototype.push = setCacheAdd;
	SetCache.prototype.has = setCacheHas;

	/**
	 * Creates a stack cache object to store key-value pairs.
	 *
	 * @private
	 * @constructor
	 * @param {Array} [entries] The key-value pairs to cache.
	 */
	function Stack(entries) {
	  var data = this.__data__ = new ListCache(entries);
	  this.size = data.size;
	}

	/**
	 * Removes all key-value entries from the stack.
	 *
	 * @private
	 * @name clear
	 * @memberOf Stack
	 */
	function stackClear() {
	  this.__data__ = new ListCache;
	  this.size = 0;
	}

	/**
	 * Removes `key` and its value from the stack.
	 *
	 * @private
	 * @name delete
	 * @memberOf Stack
	 * @param {string} key The key of the value to remove.
	 * @returns {boolean} Returns `true` if the entry was removed, else `false`.
	 */
	function stackDelete(key) {
	  var data = this.__data__,
	      result = data['delete'](key);

	  this.size = data.size;
	  return result;
	}

	/**
	 * Gets the stack value for `key`.
	 *
	 * @private
	 * @name get
	 * @memberOf Stack
	 * @param {string} key The key of the value to get.
	 * @returns {*} Returns the entry value.
	 */
	function stackGet(key) {
	  return this.__data__.get(key);
	}

	/**
	 * Checks if a stack value for `key` exists.
	 *
	 * @private
	 * @name has
	 * @memberOf Stack
	 * @param {string} key The key of the entry to check.
	 * @returns {boolean} Returns `true` if an entry for `