FQL Query Builder: a standalone JavaScript class to dynamically generate Facebook Query Language queries.

Query.js

/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2014 Keoki Zee
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 * INSTRUCTIONS
 * ============
 *
 * The `select()` and `where()` methods can either take individual arguments, or
 * an array of arguments. `WHERE` conditions passed to `where()` are joined
 * together using the string `" AND "` when `toString()` is called. `where()`
 * can be called multiple times to add additional `WHERE` conditions.
 *
 * EXAMPLES
 * ========
 *
 * Example 1
 * ---------
 *
 *     // Unix timestamp, expressed in seconds.
 *     var then = (new Date("Wed, 01 Jan 2014 00:00:00 UTC")).getTime() / 1000;
 *     var now = Math.round(Date.now() / 1000);
 *
 *     var query = (new Query('stream'))
 *       .select('post_id', 'message', 'created_id')
 *       .where('source_id = me()', 'created_time >= ' + then, 'created_time < ' + now)
 *       .orderByDesc('created_time')
 *       .limit(5000)
 *       .toString();
 *
 * Outputs
 *
 *     SELECT post_id,message,created_id
 *     FROM stream
 *     WHERE (source_id = me()) AND (created_time >= {then}) AND (created_time < {now})`
 *     ORDER BY created_time DESC
 *     LIMIT 5000
 *
 * as one line.
 *
 * Example 2
 * ---------
 *
 * This shows that arrays can be passed to `select()` and `when()`.
 *
 *     // Unix timestamp, expressed in seconds.
 *     var then = (new Date("Wed, 01 Jan 2014 00:00:00 UTC")).getTime() / 1000;
 *     var now = Math.round(Date.now() / 1000);
 *
 *     var query = (new Query('stream'))
 *       .select([
 *         'post_id',
 *         'message',
 *         'created_id'
 *       ])
 *       .where([
 *         'source_id = me()',
 *         'created_time >= ' + then,
 *         'created_time < ' + now
 *       ]);
 *
 * Example 3
 * ---------
 *
 * This shows that `when()` can be called multiple times.
 *
 *     // Unix timestamp, expressed in seconds.
 *     var then = (new Date("Wed, 01 Jan 2014 00:00:00 UTC")).getTime() / 1000;
 *     var now = Math.round(Date.now() / 1000);
 *
 *     var query = (new Query('stream'))
 *       .select('post_id', 'message', 'created_id')
 *       .where('source_id = me()')
 *       .where('created_time >= ' + then)
 *       .where('created_time < ' + now);
 */
 var Query = (function () {
  function Query (table) {
    this._table = table;
    this._conditions = [];
    this._fields = [];
    this._orderByField = null;
    this._orderDirection = null;
    this._max = null;
    return this;
  }

  Query.prototype.select = function () {
    var fields = arguments[0];
    if (!Array.isArray(fields)) {
      fields = Array.prototype.slice.call(arguments);
    }

    this._fields = fields;

    return this;
  }

  Query.prototype.where = function () {
    var conditions = arguments[0];
    if (!Array.isArray(conditions)) {
      conditions = Array.prototype.slice.call(arguments);
    }

    this._conditions = this._conditions.concat(conditions);

    return this;
  }

  Query.prototype.orderByField = function (field) {
    this._orderByField = field;
    this._orderDirection = ' ASC';
    return this;
  }

  Query.prototype.orderByDesc = function (field) {
    this._orderByField = field;
    this._orderDirection = ' DESC';
    return this;
  }

  Query.prototype.limit = function (limit) {
    this._max = limit;
    return this;
  }

  Query.prototype.toString = function () {
    var query = [
      'SELECT ' + this._fields.join(','),
      'FROM ' + this._table
    ];
    var temp = '';

    if (this._conditions.length) {
      temp = 'WHERE ' + this._conditions
        .map(function (c) { return '(' + c + ')'; })
        .join(' AND ');

      query.push(temp);
    }

    if (this._orderByField) {
      query.push('ORDER BY ' + this._orderByField + this._orderDirection);
    }

    if (this._max) {
      query.push('LIMIT ' + this._max);
    }

    return query.join(' ');
  };

  return Query;
})();

One of the issues with this class is that it doesn't sanitize input, so that is something that can be improved on.