index.js

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

/**
 * lodash (Custom Build) <https://lodash.com/>
 * Build: `lodash modularize exports="npm" -o ./`
 * Copyright jQuery Foundation and other contributors <https://jquery.org/>
 * 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
 */

/** Used as references for various `Number` constants. */
var INFINITY = 1 / 0;

/** `Object#toString` result references. */
var symbolTag = '[object Symbol]';

/** Used to match Latin Unicode letters (excluding mathematical operators). */
var reLatin = /[\xc0-\xd6\xd8-\xf6\xf8-\xff\u0100-\u017f]/g;

/** Used to compose unicode character classes. */
var rsComboMarksRange = '\\u0300-\\u036f\\ufe20-\\ufe23',
    rsComboSymbolsRange = '\\u20d0-\\u20f0';

/** Used to compose unicode capture groups. */
var rsCombo = '[' + rsComboMarksRange + rsComboSymbolsRange + ']';

/**
 * Used to match [combining diacritical marks](https://en.wikipedia.org/wiki/Combining_Diacritical_Marks) and
 * [combining diacritical marks for symbols](https://en.wikipedia.org/wiki/Combining_Diacritical_Marks_for_Symbols).
 */
var reComboMark = RegExp(rsCombo, 'g');

/** Used to map Latin Unicode letters to basic Latin letters. */
var deburredLetters = {
  // Latin-1 Supplement block.
  '\xc0': 'A',  '\xc1': 'A', '\xc2': 'A', '\xc3': 'A', '\xc4': 'A', '\xc5': 'A',
  '\xe0': 'a',  '\xe1': 'a', '\xe2': 'a', '\xe3': 'a', '\xe4': 'a', '\xe5': 'a',
  '\xc7': 'C',  '\xe7': 'c',
  '\xd0': 'D',  '\xf0': 'd',
  '\xc8': 'E',  '\xc9': 'E', '\xca': 'E', '\xcb': 'E',
  '\xe8': 'e',  '\xe9': 'e', '\xea': 'e', '\xeb': 'e',
  '\xcc': 'I',  '\xcd': 'I', '\xce': 'I', '\xcf': 'I',
  '\xec': 'i',  '\xed': 'i', '\xee': 'i', '\xef': 'i',
  '\xd1': 'N',  '\xf1': 'n',
  '\xd2': 'O',  '\xd3': 'O', '\xd4': 'O', '\xd5': 'O', '\xd6': 'O', '\xd8': 'O',
  '\xf2': 'o',  '\xf3': 'o', '\xf4': 'o', '\xf5': 'o', '\xf6': 'o', '\xf8': 'o',
  '\xd9': 'U',  '\xda': 'U', '\xdb': 'U', '\xdc': 'U',
  '\xf9': 'u',  '\xfa': 'u', '\xfb': 'u', '\xfc': 'u',
  '\xdd': 'Y',  '\xfd': 'y', '\xff': 'y',
  '\xc6': 'Ae', '\xe6': 'ae',
  '\xde': 'Th', '\xfe': 'th',
  '\xdf': 'ss',
  // Latin Extended-A block.
  '\u0100': 'A',  '\u0102': 'A', '\u0104': 'A',
  '\u0101': 'a',  '\u0103': 'a', '\u0105': 'a',
  '\u0106': 'C',  '\u0108': 'C', '\u010a': 'C', '\u010c': 'C',
  '\u0107': 'c',  '\u0109': 'c', '\u010b': 'c', '\u010d': 'c',
  '\u010e': 'D',  '\u0110': 'D', '\u010f': 'd', '\u0111': 'd',
  '\u0112': 'E',  '\u0114': 'E', '\u0116': 'E', '\u0118': 'E', '\u011a': 'E',
  '\u0113': 'e',  '\u0115': 'e', '\u0117': 'e', '\u0119': 'e', '\u011b': 'e',
  '\u011c': 'G',  '\u011e': 'G', '\u0120': 'G', '\u0122': 'G',
  '\u011d': 'g',  '\u011f': 'g', '\u0121': 'g', '\u0123': 'g',
  '\u0124': 'H',  '\u0126': 'H', '\u0125': 'h', '\u0127': 'h',
  '\u0128': 'I',  '\u012a': 'I', '\u012c': 'I', '\u012e': 'I', '\u0130': 'I',
  '\u0129': 'i',  '\u012b': 'i', '\u012d': 'i', '\u012f': 'i', '\u0131': 'i',
  '\u0134': 'J',  '\u0135': 'j',
  '\u0136': 'K',  '\u0137': 'k', '\u0138': 'k',
  '\u0139': 'L',  '\u013b': 'L', '\u013d': 'L', '\u013f': 'L', '\u0141': 'L',
  '\u013a': 'l',  '\u013c': 'l', '\u013e': 'l', '\u0140': 'l', '\u0142': 'l',
  '\u0143': 'N',  '\u0145': 'N', '\u0147': 'N', '\u014a': 'N',
  '\u0144': 'n',  '\u0146': 'n', '\u0148': 'n', '\u014b': 'n',
  '\u014c': 'O',  '\u014e': 'O', '\u0150': 'O',
  '\u014d': 'o',  '\u014f': 'o', '\u0151': 'o',
  '\u0154': 'R',  '\u0156': 'R', '\u0158': 'R',
  '\u0155': 'r',  '\u0157': 'r', '\u0159': 'r',
  '\u015a': 'S',  '\u015c': 'S', '\u015e': 'S', '\u0160': 'S',
  '\u015b': 's',  '\u015d': 's', '\u015f': 's', '\u0161': 's',
  '\u0162': 'T',  '\u0164': 'T', '\u0166': 'T',
  '\u0163': 't',  '\u0165': 't', '\u0167': 't',
  '\u0168': 'U',  '\u016a': 'U', '\u016c': 'U', '\u016e': 'U', '\u0170': 'U', '\u0172': 'U',
  '\u0169': 'u',  '\u016b': 'u', '\u016d': 'u', '\u016f': 'u', '\u0171': 'u', '\u0173': 'u',
  '\u0174': 'W',  '\u0175': 'w',
  '\u0176': 'Y',  '\u0177': 'y', '\u0178': 'Y',
  '\u0179': 'Z',  '\u017b': 'Z', '\u017d': 'Z',
  '\u017a': 'z',  '\u017c': 'z', '\u017e': 'z',
  '\u0132': 'IJ', '\u0133': 'ij',
  '\u0152': 'Oe', '\u0153': 'oe',
  '\u0149': "'n", '\u017f': 'ss'
};

/** 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')();

/**
 * The base implementation of `_.propertyOf` without support for deep paths.
 *
 * @private
 * @param {Object} object The object to query.
 * @returns {Function} Returns the new accessor function.
 */
function basePropertyOf(object) {
  return function(key) {
    return object == null ? undefined : object[key];
  };
}

/**
 * Used by `_.deburr` to convert Latin-1 Supplement and Latin Extended-A
 * letters to basic Latin letters.
 *
 * @private
 * @param {string} letter The matched letter to deburr.
 * @returns {string} Returns the deburred letter.
 */
var deburrLetter = basePropertyOf(deburredLetters);

/** Used for built-in method references. */
var objectProto = Object.prototype;

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

/** Built-in value references. */
var Symbol = root.Symbol;

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

/**
 * The base implementation of `_.toString` which doesn't convert nullish
 * values to empty strings.
 *
 * @private
 * @param {*} value The value to process.
 * @returns {string} Returns the string.
 */
function baseToString(value) {
  // Exit early for strings to avoid a performance hit in some environments.
  if (typeof value == 'string') {
    return value;
  }
  if (isSymbol(value)) {
    return symbolToString ? symbolToString.call(value) : '';
  }
  var result = (value + '');
  return (result == '0' && (1 / value) == -INFINITY) ? '-0' : result;
}

/**
 * Checks if `value` is object-like. A value is object-like if it's not `null`
 * and has a `typeof` result of "object".
 *
 * @static
 * @memberOf _
 * @since 4.0.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is object-like, else `false`.
 * @example
 *
 * _.isObjectLike({});
 * // => true
 *
 * _.isObjectLike([1, 2, 3]);
 * // => true
 *
 * _.isObjectLike(_.noop);
 * // => false
 *
 * _.isObjectLike(null);
 * // => false
 */
function isObjectLike(value) {
  return !!value && typeof value == 'object';
}

/**
 * Checks if `value` is classified as a `Symbol` primitive or object.
 *
 * @static
 * @memberOf _
 * @since 4.0.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is a symbol, else `false`.
 * @example
 *
 * _.isSymbol(Symbol.iterator);
 * // => true
 *
 * _.isSymbol('abc');
 * // => false
 */
function isSymbol(value) {
  return typeof value == 'symbol' ||
    (isObjectLike(value) && objectToString.call(value) == symbolTag);
}

/**
 * Converts `value` to a string. An empty string is returned for `null`
 * and `undefined` values. The sign of `-0` is preserved.
 *
 * @static
 * @memberOf _
 * @since 4.0.0
 * @category Lang
 * @param {*} value The value to process.
 * @returns {string} Returns the string.
 * @example
 *
 * _.toString(null);
 * // => ''
 *
 * _.toString(-0);
 * // => '-0'
 *
 * _.toString([1, 2, 3]);
 * // => '1,2,3'
 */
function toString(value) {
  return value == null ? '' : baseToString(value);
}

/**
 * Deburrs `string` by converting
 * [Latin-1 Supplement](https://en.wikipedia.org/wiki/Latin-1_Supplement_(Unicode_block)#Character_table)
 * and [Latin Extended-A](https://en.wikipedia.org/wiki/Latin_Extended-A)
 * letters to basic Latin letters and removing
 * [combining diacritical marks](https://en.wikipedia.org/wiki/Combining_Diacritical_Marks).
 *
 * @static
 * @memberOf _
 * @since 3.0.0
 * @category String
 * @param {string} [string=''] The string to deburr.
 * @returns {string} Returns the deburred string.
 * @example
 *
 * _.deburr('déjà vu');
 * // => 'deja vu'
 */
function deburr(string) {
  string = toString(string);
  return string && string.replace(reLatin, deburrLetter).replace(reComboMark, '');
}

var lodash_deburr = deburr;

const compose = (...fns) => (arg) => fns.reduceRight((acc, curr) => curr(acc), arg);

const replaceNonAlphaNumeric = (string) => string.replace(/\W+/g, ' ');

const split = (string) => string.split(' ');

const filter = (predicate) => (items) => items.filter(predicate);

const toLowerCase = (string) => string.toLowerCase();

const trim = (string) => string.trim();

const normalizeFields = (options = {}) => {
    return Object.fromEntries(
        Object
            .entries(options)
            .map(([key, value]) => [
                key,
                typeof value === 'string' ?
                    (doc) => doc.get(value) :
                    value
            ])
    );
};

const createSchemaFields = ({fields = {}, select = false} = {}) => Object.fromEntries(
    Object
        .keys(fields)
        .map((key) => [key, {type: [String], select}])
);

const getWords = compose(
    filter(Boolean),
    split,
    replaceNonAlphaNumeric,
    lodash_deburr,
    toLowerCase,
    trim
);

const normalizeInputFactory = (fields) => {
    const fieldNames = Object.keys(fields);
    return (input) => {
        if (typeof input === 'string') {
            return Object.fromEntries(
                fieldNames.map((key) => [key, {
                    searchQuery: input,
                    weight: 1
                }])
            );
        }
        
        return Object.fromEntries(
            Object
                .entries(input)
                .filter(([key]) => fieldNames.includes(key))
                .map(([key, value]) => {
                    const inputObject = typeof value === 'string' ? {searchQuery: value} : value;
                    if (!(inputObject && inputObject.searchQuery)) {
                        throw new Error(`you must provide at least "searchQuery" property for the query field ${key}. Ex:
                        {
                            ${key}:{
                                searchQuery: 'some query string',
                                // weight: 4, // and eventually a weight
                            }
                        }
                        `);
                    }
                    
                    return [key, {
                        searchQuery: inputObject.searchQuery,
                        weight: inputObject.weight || 1
                    }];
                })
        );
    };
};

const totalWeight = (normalizedInput) => Object
    .values(normalizedInput)
    .reduce((acc, curr) => acc + curr.weight, 0);

const individualSimilarityClause = ([path, input]) => {
    const trigram = sentenceTrigrams(input.searchQuery);
    return {
        $multiply: [input.weight, {
            $divide: [{
                $size: {
                    $setIntersection: [`$${path}`, trigram]
                }
            },
                trigram.length]
        }]
    };
};

const buildSimilarityClause = (normalizedInput) => {
    return {
        $divide: [{$add: Object.entries(normalizedInput).map(individualSimilarityClause)}, totalWeight(normalizedInput)]
    };
};

const buildMatchClause = (normalizedInput) => Object.fromEntries(
    Object
        .entries(normalizedInput)
        .map(([key, value]) => [key, {$in: sentenceTrigrams(value.searchQuery)}])
);

const leftPad = (length, {symbol = ' '} = {}) => (string) => string.padStart(length + string.length, symbol);
const rightPad = (length, {symbol = ' '} = {}) => (string) => string.padEnd(length + string.length, symbol);
const addPadding = (length, opts = {}) => compose(leftPad(length, opts), rightPad(length, opts));
const removeDuplicate = (array) => [...new Set(array)];

const nGram = (n, {withPadding = false} = {withPadding: false}) => {
    
    const wholeNGrams = (string, accumulator = []) => {
        if (string.length < n) {
            return accumulator;
        }
        accumulator.push(string.slice(0, n));
        return wholeNGrams(string.slice(1), accumulator);
    };
    
    const pad = addPadding(n - 1);
    
    return withPadding ? compose(removeDuplicate, wholeNGrams, pad) : compose(removeDuplicate, wholeNGrams);
};

const trigram = nGram(3, {withPadding: true});

const combineTriGrams = (string) => getWords(string)
    .map(trigram)
    .reduce((acc, curr) => acc.concat(curr), []);

const sentenceTrigrams = compose(removeDuplicate, combineTriGrams);

/**
 * lodash (Custom Build) <https://lodash.com/>
 * Build: `lodash modularize exports="npm" -o ./`
 * Copyright jQuery Foundation and other contributors <https://jquery.org/>
 * 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
 */

/** Used as the `TypeError` message for "Functions" methods. */
var FUNC_ERROR_TEXT = 'Expected a function';

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

/** Used as references for various `Number` constants. */
var INFINITY$1 = 1 / 0,
    MAX_SAFE_INTEGER = 9007199254740991;

/** `Object#toString` result references. */
var funcTag = '[object Function]',
    genTag = '[object GeneratorFunction]',
    symbolTag$1 = '[object Symbol]';

/** Used to match property names within property paths. */
var reIsDeepProp = /\.|\[(?:[^[\]]*|(["'])(?:(?!\1)[^\\]|\\.)*?\1)\]/,
    reIsPlainProp = /^\w*$/,
    reLeadingDot = /^\./,
    rePropName = /[^.[\]]+|\[(?:(-?\d+(?:\.\d+)?)|(["'])((?:(?!\2)[^\\]|\\.)*?)\2)\]|(?=(?:\.|\[\])(?:\.|\[\]|$))/g;

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

/** Used to match backslashes in property paths. */
var reEscapeChar = /\\(\\)?/g;

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

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

/** Detect free variable `global` from Node.js. */
var freeGlobal$1 = typeof commonjsGlobal == 'object' && commonjsGlobal && commonjsGlobal.Object === Object && commonjsGlobal;

/** Detect free variable `self`. */
var freeSelf$1 = typeof self == 'object' && self && self.Object === Object && self;

/** Used as a reference to the global object. */
var root$1 = freeGlobal$1 || freeSelf$1 || Function('return this')();

/**
 * 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];
}

/**
 * Checks if `value` is a host object in IE < 9.
 *
 * @private
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is a host object, else `false`.
 */
function isHostObject(value) {
  // Many host objects are `Object` objects that can coerce to strings
  // despite having improperly defined `toString` methods.
  var result = false;
  if (value != null && typeof value.toString != 'function') {
    try {
      result = !!(value + '');
    } catch (e) {}
  }
  return result;
}

/** Used for built-in method references. */
var arrayProto = Array.prototype,
    funcProto = Function.prototype,
    objectProto$1 = Object.prototype;

/** Used to detect overreaching core-js shims. */
var coreJsData = root$1['__core-js_shared__'];

/** 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 decompiled source of functions. */
var funcToString = funcProto.toString;

/** Used to check objects for own properties. */
var hasOwnProperty = objectProto$1.hasOwnProperty;

/**
 * Used to resolve the
 * [`toStringTag`](http://ecma-international.org/ecma-262/7.0/#sec-object.prototype.tostring)
 * of values.
 */
var objectToString$1 = objectProto$1.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 Symbol$1 = root$1.Symbol,
    splice = arrayProto.splice;

/* Built-in method references that are verified to be native. */
var Map = getNative(root$1, 'Map'),
    nativeCreate = getNative(Object, 'create');

/** Used to convert symbols to primitives and strings. */
var symbolProto$1 = Symbol$1 ? Symbol$1.prototype : undefined,
    symbolToString$1 = symbolProto$1 ? symbolProto$1.toString : undefined;

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

  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) : {};
}

/**
 * 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) {
  return this.has(key) && delete this.__data__[key];
}

/**
 * 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__;
  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 ? entries.length : 0;

  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__ = [];
}

/**
 * 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);
  }
  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) {
    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 ? entries.length : 0;

  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.__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) {
  return getMapData(this, key)['delete'](key);
}

/**
 * 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) {
  getMapData(this, key).set(key, value);
  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;

/**
 * Assigns `value` to `key` of `object` if the existing value is not equivalent
 * using [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
 * for equality comparisons.
 *
 * @private
 * @param {Object} object The object to modify.
 * @param {string} key The key of the property to assign.
 * @param {*} value The value to assign.
 */
function assignValue(object, key, value) {
  var objValue = object[key];
  if (!(hasOwnProperty.call(object, key) && eq(objValue, value)) ||
      (value === undefined && !(key in object))) {
    object[key] = value;
  }
}

/**
 * Gets the index at which the `key` is found in `array` of key-value pairs.
 *
 * @private
 * @param {Array} array The array to inspect.
 * @param {*} key The key to search for.
 * @returns {number} Returns the index of the matched value, else `-1`.
 */
function assocIndexOf(array, key) {
  var length = array.length;
  while (length--) {
    if (eq(array[length][0], key)) {
      return length;
    }
  }
  return -1;
}

/**
 * The base implementation of `_.isNative` without bad shim checks.
 *
 * @private
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is a native function,
 *  else `false`.
 */
function baseIsNative(value) {
  if (!isObject(value) || isMasked(value)) {
    return false;
  }
  var pattern = (isFunction(value) || isHostObject(value)) ? reIsNative : reIsHostCtor;
  return pattern.test(toSource(value));
}

/**
 * The base implementation of `_.set`.
 *
 * @private
 * @param {Object} object The object to modify.
 * @param {Array|string} path The path of the property to set.
 * @param {*} value The value to set.
 * @param {Function} [customizer] The function to customize path creation.
 * @returns {Object} Returns `object`.
 */
function baseSet(object, path, value, customizer) {
  if (!isObject(object)) {
    return object;
  }
  path = isKey(path, object) ? [path] : castPath(path);

  var index = -1,
      length = path.length,
      lastIndex = length - 1,
      nested = object;

  while (nested != null && ++index < length) {
    var key = toKey(path[index]),
        newValue = value;

    if (index != lastIndex) {
      var objValue = nested[key];
      newValue = customizer ? customizer(objValue, key, nested) : undefined;
      if (newValue === undefined) {
        newValue = isObject(objValue)
          ? objValue
          : (isIndex(path[index + 1]) ? [] : {});
      }
    }
    assignValue(nested, key, newValue);
    nested = nested[key];
  }
  return object;
}

/**
 * The base implementation of `_.toString` which doesn't convert nullish
 * values to empty strings.
 *
 * @private
 * @param {*} value The value to process.
 * @returns {string} Returns the string.
 */
function baseToString$1(value) {
  // Exit early for strings to avoid a performance hit in some environments.
  if (typeof value == 'string') {
    return value;
  }
  if (isSymbol$1(value)) {
    return symbolToString$1 ? symbolToString$1.call(value) : '';
  }
  var result = (value + '');
  return (result == '0' && (1 / value) == -INFINITY$1) ? '-0' : result;
}

/**
 * Casts `value` to a path array if it's not one.
 *
 * @private
 * @param {*} value The value to inspect.
 * @returns {Array} Returns the cast property path array.
 */
function castPath(value) {
  return isArray(value) ? value : stringToPath(value);
}

/**
 * Gets the data for `map`.
 *
 * @private
 * @param {Object} map The map to query.
 * @param {string} key The reference key.
 * @returns {*} Returns the map data.
 */
function getMapData(map, key) {
  var data = map.__data__;
  return isKeyable(key)
    ? data[typeof key == 'string' ? 'string' : 'hash']
    : data.map;
}

/**
 * Gets the native function at `key` of `object`.
 *
 * @private
 * @param {Object} object The object to query.
 * @param {string} key The key of the method to get.
 * @returns {*} Returns the function if it's native, else `undefined`.
 */
function getNative(object, key) {
  var value = getValue(object, key);
  return baseIsNative(value) ? value : undefined;
}

/**
 * Checks if `value` is a valid array-like index.
 *
 * @private
 * @param {*} value The value to check.
 * @param {number} [length=MAX_SAFE_INTEGER] The upper bounds of a valid index.
 * @returns {boolean} Returns `true` if `value` is a valid index, else `false`.
 */
function isIndex(value, length) {
  length = length == null ? MAX_SAFE_INTEGER : length;
  return !!length &&
    (typeof value == 'number' || reIsUint.test(value)) &&
    (value > -1 && value % 1 == 0 && value < length);
}

/**
 * Checks if `value` is a property name and not a property path.
 *
 * @private
 * @param {*} value The value to check.
 * @param {Object} [object] The object to query keys on.
 * @returns {boolean} Returns `true` if `value` is a property name, else `false`.
 */
function isKey(value, object) {
  if (isArray(value)) {
    return false;
  }
  var type = typeof value;
  if (type == 'number' || type == 'symbol' || type == 'boolean' ||
      value == null || isSymbol$1(value)) {
    return true;
  }
  return reIsPlainProp.test(value) || !reIsDeepProp.test(value) ||
    (object != null && value in Object(object));
}

/**
 * Checks if `value` is suitable for use as unique object key.
 *
 * @private
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is suitable, else `false`.
 */
function isKeyable(value) {
  var type = typeof value;
  return (type == 'string' || type == 'number' || type == 'symbol' || type == 'boolean')
    ? (value !== '__proto__')
    : (value === null);
}

/**
 * Checks if `func` has its source masked.
 *
 * @private
 * @param {Function} func The function to check.
 * @returns {boolean} Returns `true` if `func` is masked, else `false`.
 */
function isMasked(func) {
  return !!maskSrcKey && (maskSrcKey in func);
}

/**
 * Converts `string` to a property path array.
 *
 * @private
 * @param {string} string The string to convert.
 * @returns {Array} Returns the property path array.
 */
var stringToPath = memoize(function(string) {
  string = toString$1(string);

  var result = [];
  if (reLeadingDot.test(string)) {
    result.push('');
  }
  string.replace(rePropName, function(match, number, quote, string) {
    result.push(quote ? string.replace(reEscapeChar, '$1') : (number || match));
  });
  return result;
});

/**
 * Converts `value` to a string key if it's not a string or symbol.
 *
 * @private
 * @param {*} value The value to inspect.
 * @returns {string|symbol} Returns the key.
 */
function toKey(value) {
  if (typeof value == 'string' || isSymbol$1(value)) {
    return value;
  }
  var result = (value + '');
  return (result == '0' && (1 / value) == -INFINITY$1) ? '-0' : result;
}

/**
 * Converts `func` to its source code.
 *
 * @private
 * @param {Function} func The function to process.
 * @returns {string} Returns the source code.
 */
function toSource(func) {
  if (func != null) {
    try {
      return funcToString.call(func);
    } catch (e) {}
    try {
      return (func + '');
    } catch (e) {}
  }
  return '';
}

/**
 * Creates a function that memoizes the result of `func`. If `resolver` is
 * provided, it determines the cache key for storing the result based on the
 * arguments provided to the memoized function. By default, the first argument
 * provided to the memoized function is used as the map cache key. The `func`
 * is invoked with the `this` binding of the memoized function.
 *
 * **Note:** The cache is exposed as the `cache` property on the memoized
 * function. Its creation may be customized by replacing the `_.memoize.Cache`
 * constructor with one whose instances implement the
 * [`Map`](http://ecma-international.org/ecma-262/7.0/#sec-properties-of-the-map-prototype-object)
 * method interface of `delete`, `get`, `has`, and `set`.
 *
 * @static
 * @memberOf _
 * @since 0.1.0
 * @category Function
 * @param {Function} func The function to have its output memoized.
 * @param {Function} [resolver] The function to resolve the cache key.
 * @returns {Function} Returns the new memoized function.
 * @example
 *
 * var object = { 'a': 1, 'b': 2 };
 * var other = { 'c': 3, 'd': 4 };
 *
 * var values = _.memoize(_.values);
 * values(object);
 * // => [1, 2]
 *
 * values(other);
 * // => [3, 4]
 *
 * object.a = 2;
 * values(object);
 * // => [1, 2]
 *
 * // Modify the result cache.
 * values.cache.set(object, ['a', 'b']);
 * values(object);
 * // => ['a', 'b']
 *
 * // Replace `_.memoize.Cache`.
 * _.memoize.Cache = WeakMap;
 */
function memoize(func, resolver) {
  if (typeof func != 'function' || (resolver && typeof resolver != 'function')) {
    throw new TypeError(FUNC_ERROR_TEXT);
  }
  var memoized = function() {
    var args = arguments,
        key = resolver ? resolver.apply(this, args) : args[0],
        cache = memoized.cache;

    if (cache.has(key)) {
      return cache.get(key);
    }
    var result = func.apply(this, args);
    memoized.cache = cache.set(key, result);
    return result;
  };
  memoized.cache = new (memoize.Cache || MapCache);
  return memoized;
}

// Assign cache to `_.memoize`.
memoize.Cache = MapCache;

/**
 * Performs a
 * [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
 * comparison between two values to determine if they are equivalent.
 *
 * @static
 * @memberOf _
 * @since 4.0.0
 * @category Lang
 * @param {*} value The value to compare.
 * @param {*} other The other value to compare.
 * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
 * @example
 *
 * var object = { 'a': 1 };
 * var other = { 'a': 1 };
 *
 * _.eq(object, object);
 * // => true
 *
 * _.eq(object, other);
 * // => false
 *
 * _.eq('a', 'a');
 * // => true
 *
 * _.eq('a', Object('a'));
 * // => false
 *
 * _.eq(NaN, NaN);
 * // => true
 */
function eq(value, other) {
  return value === other || (value !== value && other !== other);
}

/**
 * Checks if `value` is classified as an `Array` object.
 *
 * @static
 * @memberOf _
 * @since 0.1.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is an array, else `false`.
 * @example
 *
 * _.isArray([1, 2, 3]);
 * // => true
 *
 * _.isArray(document.body.children);
 * // => false
 *
 * _.isArray('abc');
 * // => false
 *
 * _.isArray(_.noop);
 * // => false
 */
var isArray = Array.isArray;

/**
 * Checks if `value` is classified as a `Function` object.
 *
 * @static
 * @memberOf _
 * @since 0.1.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is a function, else `false`.
 * @example
 *
 * _.isFunction(_);
 * // => true
 *
 * _.isFunction(/abc/);
 * // => false
 */
function isFunction(value) {
  // The use of `Object#toString` avoids issues with the `typeof` operator
  // in Safari 8-9 which returns 'object' for typed array and other constructors.
  var tag = isObject(value) ? objectToString$1.call(value) : '';
  return tag == funcTag || tag == genTag;
}

/**
 * Checks if `value` is the
 * [language type](http://www.ecma-international.org/ecma-262/7.0/#sec-ecmascript-language-types)
 * of `Object`. (e.g. arrays, functions, objects, regexes, `new Number(0)`, and `new String('')`)
 *
 * @static
 * @memberOf _
 * @since 0.1.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is an object, else `false`.
 * @example
 *
 * _.isObject({});
 * // => true
 *
 * _.isObject([1, 2, 3]);
 * // => true
 *
 * _.isObject(_.noop);
 * // => true
 *
 * _.isObject(null);
 * // => false
 */
function isObject(value) {
  var type = typeof value;
  return !!value && (type == 'object' || type == 'function');
}

/**
 * Checks if `value` is object-like. A value is object-like if it's not `null`
 * and has a `typeof` result of "object".
 *
 * @static
 * @memberOf _
 * @since 4.0.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is object-like, else `false`.
 * @example
 *
 * _.isObjectLike({});
 * // => true
 *
 * _.isObjectLike([1, 2, 3]);
 * // => true
 *
 * _.isObjectLike(_.noop);
 * // => false
 *
 * _.isObjectLike(null);
 * // => false
 */
function isObjectLike$1(value) {
  return !!value && typeof value == 'object';
}

/**
 * Checks if `value` is classified as a `Symbol` primitive or object.
 *
 * @static
 * @memberOf _
 * @since 4.0.0
 * @category Lang
 * @param {*} value The value to check.
 * @returns {boolean} Returns `true` if `value` is a symbol, else `false`.
 * @example
 *
 * _.isSymbol(Symbol.iterator);
 * // => true
 *
 * _.isSymbol('abc');
 * // => false
 */
function isSymbol$1(value) {
  return typeof value == 'symbol' ||
    (isObjectLike$1(value) && objectToString$1.call(value) == symbolTag$1);
}

/**
 * Converts `value` to a string. An empty string is returned for `null`
 * and `undefined` values. The sign of `-0` is preserved.
 *
 * @static
 * @memberOf _
 * @since 4.0.0
 * @category Lang
 * @param {*} value The value to process.
 * @returns {string} Returns the string.
 * @example
 *
 * _.toString(null);
 * // => ''
 *
 * _.toString(-0);
 * // => '-0'
 *
 * _.toString([1, 2, 3]);
 * // => '1,2,3'
 */
function toString$1(value) {
  return value == null ? '' : baseToString$1(value);
}

/**
 * Sets the value at `path` of `object`. If a portion of `path` doesn't exist,
 * it's created. Arrays are created for missing index properties while objects
 * are created for all other missing properties. Use `_.setWith` to customize
 * `path` creation.
 *
 * **Note:** This method mutates `object`.
 *
 * @static
 * @memberOf _
 * @since 3.7.0
 * @category Object
 * @param {Object} object The object to modify.
 * @param {Array|string} path The path of the property to set.
 * @param {*} value The value to set.
 * @returns {Object} Returns `object`.
 * @example
 *
 * var object = { 'a': [{ 'b': { 'c': 3 } }] };
 *
 * _.set(object, 'a[0].b.c', 4);
 * console.log(object.a[0].b.c);
 * // => 4
 *
 * _.set(object, ['x', '0', 'y', 'z'], 5);
 * console.log(object.x[0].y.z);
 * // => 5
 */
function set(object, path, value) {
  return object == null ? object : baseSet(object, path, value);
}

var lodash_set = set;

const saveMiddleware = (fields) => function (next) {
    for (const [key, fn] of Object.entries(fields)) {
        this.set(key, sentenceTrigrams(fn(this)));
    }
    next();
};

const insertManyMiddleware = (fields) => function (next, docs) {
    const Ctr = this;
    docs.forEach((doc) => {
        for (const [path, fn] of Object.entries(fields)) {
            // we create an instance so the document given to the getter will have the Document API
            const instance = new Ctr(doc);
            // mutate doc in place only at trigram paths
            lodash_set(doc, path, sentenceTrigrams(fn(instance)));
        }
    });
    next();
};

function plugin(schema, {fields = {}, select = false} = {}) {
    
    const normalizedFields = normalizeFields(fields);
    const normalizeInput = normalizeInputFactory(fields);
    const preSave = saveMiddleware(normalizedFields);
    const preInsertMany = insertManyMiddleware(normalizedFields);
    
    schema.add(createSchemaFields({fields, select}));
    schema.pre('save', preSave);
    schema.pre('insertMany', preInsertMany);
    
    schema.statics.fuzzy = function (input) {
        const normalizedInput = normalizeInput(input);
        const matchClause = buildMatchClause(normalizedInput);
        const similarity = buildSimilarityClause(normalizedInput);
        return this.aggregate([
            {$match: matchClause},
            {
                $project: {
                    _id: 0,
                    document: '$$CURRENT',
                    similarity
                }
            }
        ]);
    };
}

export default plugin;