The console Object

The console object sits directly in the Global object. It partially implements the functionality provided by the console object found in most popular web browsers. The console object defines the following methods:

• log([arg1, ..., argN]) - write one or more objects to the standard error stream.
• info([arg1, ..., argN]) - write one or more objects to the standard error stream as informational message.
• warn([arg1, ..., argN]) - write one or more objects to the standard error stream as warning message.
• error([arg1, ..., argN]) - write one or more objects to the standard error stream as error message.

The standard error stream is typically redirected to the MySQL Error Log.

Each of the console methods log, info, error, and warn accept a variable list of arguments. A string representation of the argument values is written one after another, and a new line is written after the last argument. These functions always return null.

The log method only writes the arguments to the standard error stream. The info, warn and error methods write a message in the following format:

yyyy-mm-dd hh:mm:ss JS_DAEMON [level]: arg1...argN

Where yyyy-mm-dd hh:mm:ss is the datetime at the time of calling the method, and level is one of info, warn or error, depending on which of the methods was used. Examples:

mysql> select js('
    '>   var what = "Hello", who = "World";
    '>   console.log(what, " ", who, "!");
    '>   console.info(what, " ", who, "!");
    '>   console.warn(what, " ", who, "!");
    '>   console.error(what, " ", who, "!");
    '> ') console;
+---------+
| console |
+---------+
| null    |
+---------+
1 row in set (0.01 sec)

Messages appended to the error log:

Hello World!
2013-07-04 14:25:44 JS_DAEMON [info]: Hello World!
2013-07-04 14:25:44 JS_DAEMON [warn]: Hello World!
2013-07-04 14:25:44 JS_DAEMON [error]: Hello World!