Webscript controller : Just a misunderstood about null value

[zomurn]

Hi,

I'am currently debugging a webscript (not of mine) turning on all debugging features for web script in alfresco, more precisely a controller named categories.get.js ; here a portion of code of it :

for(var i = 0; i < categories.length; i++) {
      var result = connector.get("/deckshare/categoryChildren/path/"+categories[i]);
      logger.log("result1"+result==null);
      logger.log("result2:"+result=='null');
      logger.log("result3:"+result=="null");
      if(result != null && result != "") {
         logger.log("result="+result);
                        …
                }
}‍‍‍‍‍‍‍‍‍‍‍

And the output result is :

16:29:08,697 DEBUG [org.alfresco.repo.jscript.ScriptLogger] false
16:29:08,697 DEBUG [org.alfresco.repo.jscript.ScriptLogger] false
16:29:08,697 DEBUG [org.alfresco.repo.jscript.ScriptLogger] false
16:29:08,697 DEBUG [org.alfresco.repo.jscript.ScriptLogger] result=null
16:29:08,699 ERROR [org.springframework.extensions.webscripts.AbstractRuntime] Exception from executeScript - redirecting to status template error: 00180003 Failed to execute script 'org.springframework.extensions.webscripts.ResourceStore$WebApplicationStoreScriptContent@5db3f5b4': 00180002 TypeError: Cannot read property "id" from null (/WEB-INF/webscripts/categories/categories.get.js#35)
org.springframework.extensions.webscripts.WebScriptException: 00180003 Failed to execute script 'org.springframework.extensions.webscripts.ResourceStore$WebApplicationStoreScriptContent@5db3f5b4': 00180002 TypeError: Cannot read property "id" from null (/WEB-INF/webscripts/categories/categories.get.js#35)‍‍‍‍‍‍‍

Can you explain me why the fourth line of output is "result=null" ?
And why "result1", "result2", "result3" is not displayed ?

Thanks

[amandaluniz_z]

Hi,

Check this article: http://javascript.about.com/library/blequals.htm

[zomurn]

ok thanks.
Below, another test.

Input code :

for(var i = 0; i < categories.length; i++) {
      var result = connector.get("/deckshare/categoryChildren/path/"+categories[i]);
      if(result != null && result != "" && result != undefined) {
         logger.log("isEmptyTest :");
         logger.log(isEmpty(result));
         logger.log(result);
         logger.log(String(result));
         var obj = eval('(' + result + ')');
         //for(var j = 0; j < obj.children.length; j++) {
            if(childSelected(obj, nodeId)) {
               //obj.expanded = "true";
            }
         //}
         results.push(obj);
      }
   }

function isEmpty(obj) {
   if (typeof obj == 'undefined' || obj === null || obj === '') return true;
   if (typeof obj == 'number' && isNaN(obj)) return true;
   if (obj instanceof Date && isNaN(Number(obj))) return true;
   return false;
}
‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Output result (space are displayed with '_' (underscore) caracter) :

12:22:41,461 DEBUG [org.alfresco.repo.jscript.ScriptLogger]_isEmptyTest_:
12:22:41,464 DEBUG [org.alfresco.repo.jscript.ScriptLogger]_false
12:22:41,464 DEBUG [org.alfresco.repo.jscript.ScriptLogger]_
12:34:37,318 DEBUG [org.alfresco.repo.jscript.ScriptLogger]_null
‍‍‍‍‍

Can someone tell me the value of the "result" variable then ?

Thanks

[amandaluniz_z]

Seems to be a string with a space: " "

[amandaluniz_z]

Sorry not… it's not a space….

[zomurn]

Yes, this is NOT a space, this is nothing.
Check again, I just have edited the code (String(result)) output added.

I don't understand this code…