`Exception in template helper: TypeError: Cannot read property 'undefined' of undefined

Question

I made a site using Telescope but when load I get this error message in my browser-console. How to fix this error.

Exception in template helper: TypeError: Cannot read property 'undefined' of undefined
    at Object.Template.avatar.helpers.size (http://localhost:3000/packages/utilities_avatar.js?76304dc56cbb0aaaef4d60c3d930750cea5ac835:96:37)
    at bindDataContext (http://localhost:3000/packages/blaze.js?a5c324925e5f6e800a4c618d71caf2848b53bf51:2880:16)
    at Blaze._wrapCatchingExceptions (http://localhost:3000/packages/blaze.js?a5c324925e5f6e800a4c618d71caf2848b53bf51:1651:16)
    at http://localhost:3000/packages/blaze.js?a5c324925e5f6e800a4c618d71caf2848b53bf51:2928:66
    at Function.Template._withTemplateInstanceFunc (http://localhost:3000/packages/blaze.js?a5c324925e5f6e800a4c618d71caf2848b53bf51:3476:12)
    at wrapHelper (http://localhost:3000/packages/blaze.js?a5c324925e5f6e800a4c618d71caf2848b53bf51:2927:27)
    at Spacebars.call (http://localhost:3000/packages/spacebars.js?7bafbe05ec09b6bbb6a3b276537e4995ab298a2f:172:18)
    at Spacebars.mustacheImpl (http://localhost:3000/packages/spacebars.js?7bafbe05ec09b6bbb6a3b276537e4995ab298a2f:109:25)
    at Object.Spacebars.mustache (http://localhost:3000/packages/spacebars.js?7bafbe05ec09b6bbb6a3b276537e4995ab298a2f:113:39)
    at Template.avatar.HTML.DIV.class (http://localhost:3000/packages/utilities_avatar.js?76304dc56cbb0aaaef4d60c3d930750cea5ac835:48:82)

Answer 1

Go and look through your app and look close to the Template's name and the helpers, events. Maybe a Template.yourtemplate.helper or Template.yourtemplate.event isnt equal with your HTML Template name

Answer 2

Here is answer for your problem: Stack-link Read about guarding, problem you have appears due to missing variable / key / method, because it is not yet loaded. It mostly works cause it gets loaded but unless it comes to webbrowser you recieve this error message.