index.js

"use strict";

var SqlService = function () {
    this.db = null;
    this.stack = {
        queries: [],
        binds: [],
    };
    this.timeout = 1000;
    this.isWaiting = false;
    this.wait = null;
    this.RN = false; // rigthNow
    this.DRT = false; // immediately

    this.console = function(type, value, message) {
        switch (type) {
            case 'required':
                console.warn(value + 'is required.');
                break;
            case 'deprecated':
                console.warn(value + ' is deprecated. + ' + message);
                break;
            default:
                break;
        }
    };

    this.rightNow = function() {
        this.RN = true;
        return this;
    };

    this.directly = function() {
        this.DRT = true;
        return this;
    };

    this.init = function(opt) {
        if (typeof opt !== 'object')
            this.console('deprecated', 'init(id, object)', 'Use init({id: \'\', dbObject: object}) instead.');
        else {
            if (!opt.dbObject)
                this.console('required', 'dbObject');
            if (!opt.id)
                this.console('required', 'id');
        }

        var object = opt.dbObject;
        var id = opt.id;
        var version = opt.version || '1.0';
        var description = opt.description || 'Database';

        this.timeout = opt.timeout || this.timeout;
        this.db = object.openDatabase(id + ".db", version, description, 200000);
    };

    this.execute = function(sql, value, type) {
        if (!this.db) {
            const error = 'DB not initialized. You can run "init" method';
            console.error(error);

            return Promise.reject(error);
        }

        var self = this;
        type = type || "array";

        return new Promise(function(resolve, reject) {
            var reset = function() {
                self.stack.queries = [];
                self.stack.binds = [];
                self.isWaiting = false;
            };

            var exec = function(doResult) {
                var queries = self.stack.queries;
                var binds = self.stack.binds;
                reset();
                if (queries.length < 1)
                    return;

                self.db.transaction(function(tx) {
                    var tmpQ, tmpB, execCount = 0, errors = [];

                    for (var i = 0; i < queries.length; i++) {
                        tmpQ = queries[i];
                        tmpB = binds[i];

                        tx.executeSql(tmpQ, tmpB, function (tx, res) {
                            execCount++;
                            if (execCount === queries.length && doResult === true) {
                                switch(type) {
                                    case 'array':
                                        var list = [];
                                        for (var i = 0; i < res.rows.length; i++)
                                            list.push(res.rows.item(i));
                                        resolve(list, errors);
                                        break;
                                    case 'object':
                                        resolve(res.rows.item(0), errors);
                                        break;
                                    default:
                                        resolve(res, errors);
                                        break;
                                }
                            }
                        }, function(tx, error) {
                            execCount++;
                            errors.push(error || tx);
                            if (execCount === queries.length && doResult === true)
                                reject(errors);
                        });
                    }
                });
            };

            if (self.RN === true || self.timeout === 0) {
                self.RN = false;

                // this option ignores any pending queries in the queue and runs first
                if (self.DRT) {
                    self.DRT = false;

                    var queries = self.stack.queries.slice();
                    var binds = self.stack.binds.slice();
                    self.stack.queries = [sql];
                    self.stack.binds = [value];
                    exec(true);

                    self.stack.queries = queries;
                    self.stack.binds = binds;
                    return;
                }
                else {
                    if (self.wait !== null)
                        clearTimeout(self.wait);

                    exec(false);
                    self.stack.queries.push(sql);
                    self.stack.binds.push(value);
                    return exec(true);
                }
            }

            self.stack.queries.push(sql);
            self.stack.binds.push(value);

            if (self.isWaiting === true) {
                return;
            }

            self.isWaiting = true;

            self.wait = setTimeout(exec, self.timeout);
        });
    };

    this.select = function(table, field, where, values, order) {
        var self = this;

        var deferred = new Promise(function(resolve, reject) {

            field = field || "*";
            var list = [];

            if (where && values) {
                var sql = 'SELECT ' + field + ' FROM ' + table + ' WHERE ' + where;
            } else {
                var sql = 'SELECT ' + field + ' FROM ' + table;
            }
            if (order)
                sql += " ORDER BY " + order;

            self.rightNow().execute(sql, values || []).then(resolve, reject);
        });

        return deferred;
    };

    this.insert = function(table, row, values) {
        var self = this;

        var deferred = new Promise(function(resolve, reject) {
            var sql = 'INSERT INTO ' + table + ' (';
            for (var i = 0; i < row.length; i++) sql += row[i] + ",";
            sql = sql.slice(0, sql.length - 1);
            sql += ') VALUES ';

            if (typeof values[0] == "object" && values[0]) {
                for (var i = 0; i < values.length; i++) {
                    sql += '(';
                    for (var j = 0; j < values[i].length; j++)
                        sql += ( j != values[i].length - 1 ) ? "'"+values[i][j]+"'," : "'"+values[i][j]+"'),";
                }
                sql = sql.slice(0, sql.length - 1);
                values = [];
            } else {
                sql += "(";
                for (var i = 0; i < values.length; i++) sql += "?,";
                sql = sql.slice(0, sql.length - 1);
                sql += ")";
            }

            self.execute(sql, values || [], "popup").then(resolve, reject);
        });

        return deferred;
    };

    this.delete = function(table, where, values) {
        var self = this;

        var deferred = new Promise(function(resolve, reject) {
            if (where && values)
                var sql = 'DELETE FROM ' + table + ' WHERE ' + where;
            else
                var sql = 'DELETE FROM ' + table;

            self.execute(sql, values || [], "popup").then(resolve, reject);
        });

        return deferred;
    };

    this.update = function(table, row, values, where, wValues) {
        var self = this;

        var deferred = new Promise(function(resolve, reject) {
            var sql = 'UPDATE ' + table + ' SET ';
            for (var i = 0; i < values.length; i++) sql += row[i] + "=?,";
            sql = sql.slice(0, sql.length - 1);
            if (where && wValues) {
                sql += " WHERE " + where;
                for (var i = 0; i < wValues.length; i++)
                    values.push(wValues[i]);
            }

            self.execute(sql, values || [], "popup").then(resolve, reject);
        });

        return deferred;
    };

    this.query = function(sql, values) {
        var self = this;
        values = values || [];

        var deferred = new Promise(function(resolve, reject) {
            var list = [];

            self.execute(sql, values, "popup", true).then(function (res) {
                for (var i = 0; i < res.rows.length; i++)
                    list.push(res.rows.item(i));
                resolve(list);
            }, reject);
        });

        return deferred;
    };
};

module.exports = SqlService;