Error - Velocity & jQuery 1.4.2 - Cannot read property 'tweensContainer' of undefined

[raphaelrauwolf]

When Velocity is used with jQuery 1.4.2 and you want to fade out an element, the browser throws the error Cannot read property 'tweensContainer' of undefined. This error is thrown, because the Data Cache has not been initiated. The reason for that is, that in the earlier jQuery Versions, $.data(element, NAME) would be null instead of undefined.

In line 1545, where you check if the Data Cache has been initiated, you additionally have to check if the data object is null.

//jQuery 1.11.1
$.data($('body'),'velocity'); // undefined

//jQuery 1.4.2
$.data($('body'),'velocity'); // null

[julianshapiro]

Hey Raphael. Thank you so much for doing the research and pinpointing this issue.

As per the package.json (https://github.com/julianshapiro/velocity/blob/master/package.json), Velocity explicitly supports 1.4.3 and up. But, I'm going to make this tweak now and see if this was the only issue preventing Velocity from working on 1.4.2! Stay tuned.

You are awesome. Thanks again.

[julianshapiro]

Ok, so while addressing this issue does solve the problem, jQuery below 1.4.3 has unsolved IE8-related CSS bugs. So, I cannot recommend using below 1.4.3 in any circumstance -- but at least Velocity doesn't error out now in these older versions.