advanced code snippet search

Posted By

wizard04 on 06/17/08


Tagged

javascript object window popup debug console alert breakpoint


Versions (?)

Who likes this?

2 people have marked this snippet as a favorite

SpinZ
mifly


Debug object

 / Published in: JavaScript
 

An object including a few helpful functions for debugging. Functions displaying popups or alerts are limited to a certain number of consecutive times before asking to continue, in case they end up being called in an endless loop or something.

Expand | Embed | Plain Text 
  1. if(!window.config) var config = {};
  2. config.Debug = {
  3. 	maxPopups: 5	//default number of popups/alerts allowed before asking to continue
  4. };
  5.  
  6. //static Debug object
  7. var Debug = function()
  8. {
  9. 	//***** private properties and methods *****//
  10.  
  11. 	var maxPopups = window.config.Debug.maxPopups;
  12. 	var debugWindow;
  13. 	var popupCount = 0;
  14. 	var continuePopups = true;
  15.  
  16. 	//write a message (HTML) to the debug window
  17. 	function write(msg)
  18. 	{
  19. 		if(!debugWindow || !debugWindow.document)
  20. 		{
  21. 			debugWindow = window.open("", "debug");	//create the debug window
  22. 			if(!debugWindow)	//a popup blocker caught it
  23. 			{
  24. 				msg = msg.replace(/<br(\s+\/)?>/ig, "\n");
  25. 				debugAlert(msg);	//use an alert instead
  26. 				return;
  27. 			}
  28. 			//debugWindow.document.open("text/html");	//it's text/html by default
  29. 			debugWindow.document.write("<html><head><title>Debug: "+document.title+"</title></head><body></body></html>");
  30. 			//note: <title> only works in Opera
  31. 			debugWindow.document.close();
  32. 		}
  33. 		debugWindow.document.title = "Debug: "+document.title;	//doesn't work in Opera
  34. 		debugWindow.document.body.innerHTML += msg+"<br />";
  35. 	}
  36. 	//write some code to the debug window
  37. 	function writeCode(code)
  38. 	{
  39. 		code = code.replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;");
  40. 		write('<pre style="background-color:#EEEEEE; margin:1em 0; min-height:2.5em; overflow:auto;">'+code+'</pre>');
  41. 	}
  42.  
  43. 	//log a message to the javascript/error console, if supported
  44. 	function logToConsole(msg)
  45. 	{
  46. 		if(window.console) window.console.log(msg);
  47. 	}
  48.  
  49. 	//open a new window with specified content (employs maxPopups)
  50. 	function popup(content, mimeType)
  51. 	{
  52. 		if(!continuePopups) return;
  53. 		if(popupCount >= maxPopups && popupCount % maxPopups == 0)	//for every maxPopups popups/alerts
  54. 		{
  55. 			//This is a safety mechanism in case popups/alerts are displayed in large quantities
  56. 			// (e.g., if it was called inside a loop)
  57. 			continuePopups = window.confirm(popupCount+" debug popups have been displayed. Continue?");
  58. 			if(!continuePopups) return;
  59. 		}
  60. 		var popWindow = window.open("", "");	//create a new window
  61. 		if(!popWindow)	//a popup blocker caught it
  62. 		{
  63. 			debugAlert(content);	//use an alert instead
  64. 			return;
  65. 		}
  66. 		if(mimeType) popWindow.document.open(mimeType);	//it's text/html by default
  67. 			//As far as I know, text/xml isn't supported. In Firefox it becomes text/plain instead of text/html.
  68. 			//Also, setting mimeType to text/plain doesn't always work; use popupCode function below instead
  69. 		popWindow.document.write(content);
  70. 		popWindow.document.close();
  71. 		popWindow.document.title = "Debug Popup: "+document.title;
  72. 		popupCount++;
  73. 	}
  74. 	//open a new window with specified content as code (employs maxPopups)
  75. 	function popupCode(content)
  76. 	{
  77. 		content = content.replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;");
  78. 		popup("<pre>"+content+"</pre>");
  79. 	}
  80.  
  81. 	//displays an alert (employs maxPopups)
  82. 	function debugAlert(txt)
  83. 	{
  84. 		if(!continuePopups) return;
  85. 		if(popupCount >= maxPopups && popupCount % maxPopups == 0)	//for every maxPopups popups/alerts
  86. 		{
  87. 			//This is a safety mechanism in case popups/alerts are displayed in large quantities
  88. 			// (e.g., if it was called inside a loop)
  89. 			continuePopups = window.confirm(popupCount+" debug popups have been displayed. Continue?");
  90. 			if(!continuePopups) return;
  91. 		}
  92. 		window.alert(txt);
  93. 		popupCount++;
  94. 	}
  95.  
  96. 	//from http://code.google.com/p/trimpath/wiki/TrimBreakpoint
  97. 	//allows you to evaluate expressions in the current scope
  98. 	//usage:   Debug.breakpoint(function(s){return eval(s);}, "Note about breakpoint", "1+2");
  99. 	//the first argument is required as shown (to access the closure)
  100. 	function breakpoint(evalFunc, msg, initialExpr)
  101. 	{
  102. 		msg = msg || "";
  103. 		var result = "";
  104. 		var expr = initialExpr || "";
  105. 		if(expr)
  106. 		{
  107. 			try{
  108. 				result = evalFunc(expr);
  109. 			}catch(e){
  110. 				result = e;
  111. 			}
  112. 		}
  113. 		while(true)
  114. 		{
  115. 			expr = prompt("BREAKPOINT: " + msg + "\nEnter an expression to evaluate, or Cancel to continue.\n\nResult:\n" +
  116. 			 result, expr);
  117. 			if(!expr) return;	//cancelled or left blank
  118. 			try{
  119. 				result = evalFunc(expr);
  120. 			}catch(e){
  121. 				result = e;
  122. 			}
  123. 		}
  124. 	}
  125.  
  126. 	function resetPopups()
  127. 	{
  128. 		popupCount = 0;
  129. 		continuePopups = true;
  130. 		maxPopups = window.config.Debug.maxPopups;	//in case it changed
  131. 	}
  132.  
  133. 	//***** public properties and methods *****//
  134.  
  135. 	return {
  136. 		write: write,
  137. 		writeCode: writeCode,
  138. 		log: logToConsole,
  139. 		popup: popup,
  140. 		popupCode: popupCode,
  141. 		alert: debugAlert,
  142. 		breakpoint: breakpoint,
  143. 		resetPopups: resetPopups
  144. 	}
  145. }();	//initialize Debug

Report this snippet  

Comments

RSS Icon Subscribe to comments
Posted By: wizard04 on September 24, 2008

Updated.

You need to login to post a comment.