DB/Text trace log format method

Further to my post of May 2007, where I described how to create a trace log in DB/Text and handle exceptions, here is a method that is handy for building more complex log statements.

   1: // construct formatted log statement

   2: function logFormat(val, arg1, arg2, arg3)

   3: {

   4:     var formattedVal = val;

   5:     if (arg1 != null)    {

   6:         formattedVal = formattedVal.replace("{0}", arg1);

   7:     }

   8:     if (arg2 != null) {

   9:         formattedVal = formattedVal.replace("{1}", arg2);

  10:     }

  11:     if (arg3 != null) {

  12:         formattedVal = formattedVal.replace("{2}", arg3);

  13:     }

  14:     log(formattedVal);

  15: }

  16:  

  17: // write log statement to form box

  18: function log(val)

  19: {

  20:     var box = Form.boxes("boxDebugLog");

  21:     if (box == null)

  22:         return;    

  23:     

  24:     if (box.content != '')

  25:     {

  26:         box.content += "\n";    

  27:     }    

  28:     box.content += val;

  29: }

Overview

logFormat takes a string value and up to 3 arguments, and replaces tokens found in the string value with those arguments. It's based on C#'s string.Format method, and others like it.

Example

It's easier to read (and write) a format string that contains tokens than a string concatenated together with plus signs.

   1: var count = 10;

   2: var name = "Peter";

   3: var duration = 30;

   4:  

   5: function LogTheOldWay()

   6: {

   7:     log(name + " was lashed with a wet noodle " + count + " times for " + duration + " seconds.");

   8: }

   9:  

  10: function LogTheNewWay()

  11: {    

  12:     logFormat("{0} was lashed with a wet noodle {1} times for {2} seconds.", name, count, duration);

  13: }

Update

My example above only proves how piddly my skills really are. There's a *much* better way of doing this that allows for n arguments instead of a maximum of three. I had forgotten that every javascript function has a local property called arguments that contains all parameters passed to the function as an array.

   1: function logFormat(val)

   2: {

   3:     var formattedVal = val;

   4:   for(i = 1; i < arguments.length; i++)

   5:   {

   6:     formattedVal = formattedVal.replace("{" + (i - 1) + "}", arguments[i]);

   7:   }

   8:   return formattedVal;

   9: }