elastic-builder/lib/queries/term-level-queries/fuzzy-query.js

A JavaScript implementation of the elasticsearch Query DSL

'use strict';

var _classCallCheck2 = require('babel-runtime/helpers/classCallCheck');

var _classCallCheck3 = _interopRequireDefault(_classCallCheck2);

var _createClass2 = require('babel-runtime/helpers/createClass');

var _createClass3 = _interopRequireDefault(_createClass2);

var _possibleConstructorReturn2 = require('babel-runtime/helpers/possibleConstructorReturn');

var _possibleConstructorReturn3 = _interopRequireDefault(_possibleConstructorReturn2);

var _inherits2 = require('babel-runtime/helpers/inherits');

var _inherits3 = _interopRequireDefault(_inherits2);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

var MultiTermQueryBase = require('./multi-term-query-base');

/**
 * The fuzzy query generates all possible matching terms that are within
 * the maximum edit distance specified in `fuzziness` and then checks
 * the term dictionary to find out which of those generated terms
 * actually exist in the index.
 *
 * The fuzzy query uses similarity based on Levenshtein edit distance.
 *
 * [Elasticsearch reference](https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-fuzzy-query.html)
 *
 * @example
 * const qry = esb.fuzzyQuery('user', 'ki');
 *
 * @example
 * // More advanced settings
 * const qry = esb.fuzzyQuery('user', 'ki')
 *     .fuzziness(2)
 *     .prefixLength(0)
 *     .maxExpansions(100)
 *     .boost(1.0);
 *
 * @param {string=} field
 * @param {string|number=} value
 *
 * @extends MultiTermQueryBase
 */

var FuzzyQuery = function (_MultiTermQueryBase) {
    (0, _inherits3.default)(FuzzyQuery, _MultiTermQueryBase);

    // eslint-disable-next-line require-jsdoc
    function FuzzyQuery(field, value) {
        (0, _classCallCheck3.default)(this, FuzzyQuery);
        return (0, _possibleConstructorReturn3.default)(this, (FuzzyQuery.__proto__ || Object.getPrototypeOf(FuzzyQuery)).call(this, 'fuzzy', field, value));
    }

    /**
     * Sets the `fuzziness` parameter which is interpreted as a Levenshtein Edit Distance —
     * the number of one character changes that need to be made to one string to make it
     * the same as another string.
     *
     * @param {number|string} factor Can be specified either as a number, or the maximum
     * number of edits, or as `AUTO` which generates an edit distance based on the length
     * of the term.
     * @returns {FuzzyQuery} returns `this` so that calls can be chained.
     */


    (0, _createClass3.default)(FuzzyQuery, [{
        key: 'fuzziness',
        value: function fuzziness(factor) {
            this._queryOpts.fuzziness = factor;
            return this;
        }

        /**
         * The number of initial characters which will not be “fuzzified”.
         * This helps to reduce the number of terms which must be examined. Defaults to `0`.
         *
         * @param {number} len Characters to skip fuzzy for. Defaults to `0`.
         * @returns {FuzzyQuery} returns `this` so that calls can be chained.
         */

    }, {
        key: 'prefixLength',
        value: function prefixLength(len) {
            this._queryOpts.prefix_length = len;
            return this;
        }

        /**
         * The maximum number of terms that the fuzzy query will expand to. Defaults to `50`.
         *
         * @param {number} limit Limit for fuzzy query expansion. Defaults to `50`.
         * @returns {FuzzyQuery} returns `this` so that calls can be chained.
         */

    }, {
        key: 'maxExpansions',
        value: function maxExpansions(limit) {
            this._queryOpts.max_expansions = limit;
            return this;
        }

        /**
         * Transpositions (`ab` → `ba`) are allowed by default but can be disabled
         * by setting `transpositions` to false.
         *
         * @param {boolean} enable
         * @returns {FuzzyQuery} returns `this` so that calls can be chained.
         */

    }, {
        key: 'transpositions',
        value: function transpositions(enable) {
            this._queryOpts.transpositions = enable;
            return this;
        }
    }]);
    return FuzzyQuery;
}(MultiTermQueryBase);

module.exports = FuzzyQuery;