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easejs/lib/warn.js

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/**
* ease.js warning system
*
* Copyright (C) 2010 Mike Gerwitz
*
* This file is part of ease.js.
*
* ease.js is free software: you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License as published by the Free
* Software Foundation, either version 3 of the License, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* @author Mike Gerwitz
*/
/**
* Active warning handler
* @type {function()}
*/
var _handler = null;
/**
* Console to use for logging
*
* This reference allows an alternative console to be used. Must contain warn()
* or log() methods.
*
* @type {Object}
*/
var _console = ( typeof console !== 'undefined' ) ? console : undefined;
/**
* Permits wrapping an exception as a warning
*
* Warnings are handled differently by the system, depending on the warning
* level that has been set.
*
* @param {Error} e exception (error) to wrap
*
* @return {Warning} new warning instance
*/
var Warning = exports.Warning = function( e )
{
// allow instantiation without use of 'new' keyword
if ( !( this instanceof Warning ) )
{
return new Warning( e );
}
// ensure we're wrapping an exception
if ( !( e instanceof Error ) )
{
throw TypeError( "Must provide exception to wrap" );
}
Error.prototype.constructor.call( this, e.message );
// copy over the message for convenience
this.message = e.message;
this.name = 'Warning';
this._error = e;
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this.stack = e.stack &&
e.stack.replace( /^.*?\n+/,
this.name + ': ' + this.message + "\n"
);
};
// ensures the closest compatibility...just be careful not to modify Warning's
// prototype
Warning.prototype = Error();
Warning.prototype.constructor = Warning;
Warning.prototype.name = 'Warning';
/**
* Return the error wrapped by the warning
*
* @return {Error} wrapped error
*/
Warning.prototype.getError = function()
{
return this._error;
};
/**
* Core warning handlers
* @type {Object}
*/
exports.handlers = {
/**
* Logs message to console
*
* Will attempt to log using console.warn(), falling back to console.log()
* if necessary and aborting entirely if neither is available.
*
* This is useful as a default option to bring problems to the developer's
* attention without affecting the control flow of the software.
*
* @param {Warning} warning to log
*
* @return {undefined}
*/
log: function( warning )
{
var dest;
_console && ( dest = _console.warn || _console.log ) &&
dest( 'Warning: ' + warning.message );
},
/**
* Throws the error associated with the warning
*
* This handler is useful for development and will ensure that problems are
* brought to the attention of the developer.
*
* @param {Warning} warning to log
*
* @return {undefined}
*/
throwError: function( warning )
{
throw warning.getError();
},
/**
* Ignores warnings
*
* This is useful in a production environment where (a) warnings will affect
* the reputation of the software or (b) warnings may provide too much
* insight into the software. If using this option, you should always
* develop in a separate environment so that the system may bring warnings
* to your attention.
*
* @param {Warning} warning to log
*
* @return {undefined}
*/
dismiss: function( warning )
{
// do nothing
},
};
/**
* Sets the active warning handler
*
* You may use any of the predefined warning handlers or pass your own function.
*
* @param {function( Warning )} handler warning handler
*
* @return {undefined}
*/
exports.setHandler = function( handler )
{
_handler = handler;
};
/**
* Handles a warning using the active warning handler
*
* @param {Warning} warning warning to handle
*
* @return {undefined}
*/
exports.handle = function( warning )
{
_handler( warning );
}
/**
* Sets active console
*
* @param {Object} console containing warn() or log() method
*
* @return {undefined}
*/
exports.setConsole = function( console )
{
_console = console;
};
// set the default handler
_handler = exports.handlers.log;