TypeError undefined is not an object

Question

I have a currently fairly dysfunctional Javascript program that s been causing me problems  However  it throws one error that I just don t understand   TypeError   undefined  is not an object  evaluating  sub from length     What I m trying to do  as you can probably guess  is check the length of a certain  from  array in the sub dict  Here s the source code for the entire function  and here s the code of the loop that I think is causing the error   console log afcHelper ffuSubmissions length      just for debugging  returns the correct number for  var i   0  i  lt  afcHelper ffuSubmissions length  i         this whole section works fine     var sub   afcHelper ffuSubmissions i         console log  THIS IS BROKEN DOWN BY LINK  afcHelper Submissions i        if  pagetext indexOf afcHelper ffuSections sub section      -1               Someone has modified the section in the mean time  Skip          document getElementById  afcHelper status   innerHTML      lt li gt Skipping     sub title      Cannot find section  Perhaps it was modified in the mean time  lt  li gt            continue            var text   afcHelper ffuSections sub section       var startindex   pagetext indexOf afcHelper ffuSections sub section        var endindex   startindex   text length       console log sub        if  typeof sub from      undefined   amp  amp  sub from length  gt  0          problem spot   this is the code i recently added          for  var i   0  i  lt  sub from length  i                  mainid   sub from i   id                var sub   afcHelper Submissions mainid      and then it goes on from here      Any ideas would be great  Frankly  I just can t see why I m getting a TypeError about something that I ve already explicitly checked the type of  typeof sub from

User · Answer

try out this if you want to assign value to object and it is showing this error in angular   crate object in construtor this modelObj   new Model       lt ----------   after declaring object above

User · Answer

I m not sure how you could just check if something isn t undefined and at the same time get an error that it is undefined  What browser are you using   You could check in the following way  extra   and making length a truthy evaluation   if  typeof sub from       undefined   amp  amp  sub from length       update   I see that you reset sub and thereby reset sub from but fail to re check if sub from exist   for  var i   0  i  lt  sub from length  i        lt    assuming sub from exist             mainid   sub from i   id                var sub   afcHelper Submissions mainid       lt    re setting sub   My guess is that the error is not on the if statement but on the for i    statement  In Firebug you can break automatically on an error and I guess it ll break on that line  not on the if statement

[javascript] TypeError: 'undefined' is not an object

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