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Custom error objects in Javascript

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  1. function ErrorConstructor(constructorName) {
  2.   var errorConstructor = function(message, fileName, lineNumber) {
  3.   // don't directly name this function, .name is used by Error.prototype.toString
  4.     if (this == window) return new arguments.callee(message, fileName, lineNumber);
  5.     this.name = errorConstructor.name;
  6.     this.message = message||"";
  7.     this.fileName = fileName||location.href;
  8.     if (!isNaN(+lineNumber)) this.lineNumber = +lineNumber;
  9.     else this.lineNumber = 1;
  10.   }
  11.   errorConstructor.name = constructorName||Error.prototype.name;
  12.   errorConstructor.prototype.toString = Error.prototype.toString;
  13.  
  14.   return errorConstructor;
  15. }
  16. Usage: ErrorConstructor([constructorName])
  17.  
  18. Note: If no constructorName is specified, the default of Error.prototype.name is used
  19.  
  20. Usage for generated error constructor: errorConstructor([message[, location[, lineNumber]])
  21.  
  22. Examples:
  23.  
  24. var SecurityError = ErrorConstructor("Security Error"),
  25. MarkupError = ErrorConstructor("(X)HTML Markup Error");
  26. //these will both throw a SecurityError starting with "Security Error on line 83:"
  27. var xss_error = "Possible XSS Vector\n\
  28.  JSON XHR response parsed with eval()\n\
  29.  Recommended fix: Parse JSON with JSON.parse";
  30. throw new SecurityError(xss_error, "/js/searchResultsJSONloader.js", 83);
  31. throw SecurityError(xss_error, "/js/searchResultsJSONloader.js", 83);
  32. //these will both throw the following MarkupError:
  33. //"(X)HTML Markup Error on line 1: Invalid DOCTYPE"
  34. throw new MarkupError("Invalid DOCTYPE");
  35. throw MarkupError("Invalid DOCTYPE");

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