Javascript isnull

Question

This is a really great function written in jQuery to determine the value of a url field     urlParam   function name       var results   new RegExp       amp      name         amp        exec window location href       return results 1     0        example com someparam name amp otherparam 8 amp id 6   urlParam  someparam       name   urlParam  id       6   urlParam  notavar       null   http   snipplr com view 11583 retrieve-url-params-with-jquery   I would like to add a condition to test for null  but this looks kind of klunky   if  results    null        return 0    else       return results 1     0      Q  What s the elegant way to accomplish the above if then statement

User · Answer

the most terse solution would be to change return results 1     0  to return  results  amp  amp  results 1      0

User · Answer

I prefer the style   results       0    1

User · Answer

return results    null   0    results 1     0

User · Answer

return results    null   0     results 1     0

User · Answer

if  typeof results    undefined         return results 1     else        return 0        But you might want to check if results is an array  Arrays are of type Object so you will need this function  function typeOf value        var s   typeof value      if  s      object             if  value                if  value instanceof Array                    s    array                           else               s    null                       return s      So your code becomes  if  typeOf results     array          return results 1     else         return 0

User · Answer

Why not try  test         Try its and best boolean  true or false      urlParam   function name       var results   new RegExp       amp      name         amp             return results test window location href       Tutorial   http   www w3schools com jsref jsref regexp test asp

User · Answer

return  results  0   amp  amp  results 1     0    The  amp  amp  operator acts as guard and returns the 0 if results if falsy and return the rightmost part if truthy

User · Answer

You can also use the not operator  It will check if a variable is null  or  in the case of a string  is empty  It makes your code more compact and easier to read    For example   var pass       if  pass      return false  else     return true    This would return false because the string is empty  It would also return false if the variable pass was null

User · Answer

return results  null   0     results 1     0

User · Answer

I m using this function   function isNull         for  var i   0  i  lt  arguments length  i              if               typeof arguments i       undefined               amp  amp  arguments i      undefined              amp  amp  arguments i     null              amp  amp  arguments i     NaN              amp  amp  arguments i             return arguments i               test  console log isNull null  null  undefined   Target

User · Answer

You could try this   if typeof results      undefined          return 0    else       return results 1     0

User · Answer

All mentioned solutions are legit but if we re talking about elegance then I ll pitch in with the following example     function that checks if an object is null var isNull   function obj      return obj    null                 if isNull results     return 0    else     return results 1     0      Using the isNull function helps the code be more readable

[javascript] Javascript isnull

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