JS.Class

Introduction

• Getting started
• Supported platforms
• Package manager
• Testing tools
• License & acknowledgements

Community

• Mailing list
• GitHub repository

Core reference

• Creating classes
• Using Modules
• Modifying classes/modules
• Singleton methods
• Class methods
• Keyword methods
• Inheritance
• Method binding
• Metaprogramming hooks
• Reflection
• Debugging support
• The Kernel module
• Equality and hashing
• Interfaces
• Singletons

Standard library

• Benchmark
• Command
• Comparable
• Console
• ConstantScope
• Decorator
• Deferrable
• Enumerable
• Enumerator
• Forwardable
• Hash, OrderedHash
• LinkedList
• MethodChain
• Observable
• Proxy
• Range
• Set, OrderedSet, SortedSet
• StackTrace
• State
• TSort

Console

Most JavaScript environments have some sort of console that allows running programs to print output, log messages and the like. In many web browsers, this capability is provided by the window.console object, and in server-side environments the program may write output to the terminal. JS.Console provides a single interface to all these facilities, using the most appropriate device wherever it is being used.

When writing output to a terminal, JS.Console also supports many ANSI formatting commands for changing the color and other attributes of printed text.

The main two output methods are as follows:

• JS.Console.puts(string) – prints string to the console with a line break afterward, so that subsequent messages appear on the next line.
• JS.Console.print(string) – prints string without applying line breaks, allowing multiple print() calls to write output to the same line if the console supports this. In environments that don’t support this, the output is buffered until the next puts() call.

The output devices used are as follows:

• In web browsers that support window.console, the development console is used to log output.
• In web browsers with no console object, the alert() function is used.
• In Adobe AIR applications running under adl, the runtime.trace() function is used to write to the terminal.
• In programs running in a terminal, output is sent to STDOUT.

In addition, the following formatting commands are available for formatting output in environments that support ANSI escape codes for formatting text. All commands are methods of JS.Console, for example you can switch to bold text by calling JS.Console.bold(). Text printed after the command has been issued will have the formatting applied to it. In environments that do not support formatting these methods have no effect.

• reset() resets all formatting attributes
• bold(), normal() set the weight of the text
• underline(), noline() apply and remove underlining
• blink(), noblink() apply and remove blinking text
• black(), red(), green(), yellow(), blue(), magenta(), cyan(), white(), nocolor() set the current text color
• Color methods can be prefixed with bg, for example bgyellow(), to set the current background color

Multiple formatting instructions can be combined using this method:

JS.Console.consoleFormat('bold', 'red');

The consoleFormat() method takes a list of formatting instructions as input. It calls reset() and then applies the given formats.

Finally note that JS.Console can be used as a mixin so all the above methods appear in the current class:

Logger = new JS.Class({
    include: JS.Console,

    info: function(message) {
        this.bgblack();
        this.white();
        this.print('INFO');
        this.reset();
        this.puts(' ' + message);
    }
});