Cannot read property 'hasOwnProperty' of undefined

[dudduss]

The following code is supposed to be pasted in every page that uses amplitude:

(function(e,t){var n=e.amplitude||{_q:[],_iq:{}};var r=t.createElement("script");r.type="text/javascript"; r.async=true;r.src="https://d24n15hnbwhuhn.cloudfront.net/libs/amplitude-3.0.1-min.gz.js"; r.onload=function(){e.amplitude.runQueuedFunctions()};var i=t.getElementsByTagName("script")[0]; i.parentNode.insertBefore(r,i);function s(e,t){e.prototype[t]=function(){this._q.push([t].concat(Array.prototype.slice.call(arguments,0))); return this}}var o=function(){this._q=[];return this};var a=["add","append","clearAll","prepend","set","setOnce","unset"]; for(var u=0;u<a.length;u++){s(o,a[u])}n.Identify=o;var c=function(){this._q=[];return this; };var p=["setProductId","setQuantity","setPrice","setRevenueType","setEventProperties"]; for(var l=0;l<p.length;l++){s(c,p[l])}n.Revenue=c;var d=["init","logEvent","logRevenue","setUserId","setUserProperties","setOptOut","setVersionName","setDomain","setDeviceId","setGlobalUserProperties","identify","clearUserProperties","setGroup","logRevenueV2","regenerateDeviceId"]; function v(e){function t(t){e[t]=function(){e._q.push([t].concat(Array.prototype.slice.call(arguments,0))); }}for(var n=0;n<d.length;n++){t(d[n])}}v(n);n.getInstance=function(e){e=(!e||e.length===0?"$default_instance":e).toLowerCase(); if(!n._iq.hasOwnProperty(e)){n._iq[e]={_q:[]};v(n._iq[e])}return n._iq[e]};e.amplitude=n; })(window,document);

There is however this issue:

Cannot read property 'hasOwnProperty' of undefined

which can be found being called near the end of the amplitude code pasted above. If anyone else has run into this issue and knows how to solve it, any help would be appreciated.

[djih]

It seems n._iq is undefined, except it should be defined at the beginning of the script: var n=e.amplitude||{_q:[],_iq:{}}; The only thing I can think of is you already have a window.amplitude defined that doesn't have _iq? Is that possible?

[dingjb]

This problem is caused by include amplitude js code twice in one page.

[blazzy]

Thanks for the tips @dingjb! Hopefully your problem is solved, @dudduss. This one has been opened for a while. Closing for now.

[joker-777]

@blazzy and @dingjb
Looking at the code snippet which is also found here. It checks if window.amplitude exists before creating _iq. We still see this error in our js tracking system for some users and I was wondering if there is an important use case where window.amplitude should already exist before and should be used? Otherwise, I would just set window.amplitude = undefined before this script is executed. Any advice?

[sptaszek92]

I have the same problem. It looks like something's happening asynchronously, because the error is not always showing up. Any suggestions?

[exAspArk]

Had the same issue, it was related to loading the script multiple times with turbolinks. I fixed it by wrapping the code with an "if" statement:

<script type="text/javascript">
  if (typeof amplitude === 'undefined') {
    (function(e,t){var n=e.amplitude||{_q:[],_iq:{}};...
     ...
  }
</script>