d3.js Saved Transition Error - animation

Question

I am working in d3.js, making a chart object. My chart has an update() method that refreshes the data, using a transition to animate the change. Because I have several different objects to animate within one chart, I wanted to store the transition as a member of the Chart's prototype, then use transition.each wrapped around my transitions to allow all the transitions to inherit the settings of the outer one. I am using setTimeout to schedule updates to the chart over time, so it becomes an animation.
The chart is supposed to show the distribution of means of a skew population, as more and more means are taken. Here's a working version, where the transition is not saved as a member of the chart prototype: http://jsfiddle.net/pmwxcpz7/
Now, I try to modify the above code to store the transition during the constructor of the Chart. When I fetch the saved transition object and call transition.each() in the chart's update method, it works for the first several hundred calls, then stops working. Here's the above code, with the creation of the transition moved to the constructor: http://jsfiddle.net/whtfny15/1/
When I run the second version of the code, the chart stops animating part of the way through, and the console shows many errors saying
TypeError: t.__transition__[e] is undefined (d3.v3.min.js:5)
I have reduced the code to the minimum needed to generate the error here: http://jsfiddle.net/bw1e2vLo/1/ (note that the error shows in the console, but this script doesn't produce any visual output.)
When I run the code (in Firefox), watching the console, I get 200 errors, all of which say
TypeError: t.__transition__[e] is undefined (d3.v3.min.js:5)
I'm not sure what's going on. I would like to be able to save the transition object into my chart's prototype, so I can reuse the delay and duration settings for future animations.
Thanks for the help!

Answer 1

It's not a good idea to store D3 transitions because they are stateful -- what happens when you operate on them depends on whether they are scheduled, running, or finished. If they are finished you can't in fact do a lot with them at all, as you've discovered. In general, you should only ever manipulate a transition when creating it.
The D3 way to do multiple transitions is to re-select the elements to operate on and initialise a new transition. You can store the parameters (delay and duration) in separate variables if you want to reuse them. If you're using a custom function for the transition itself, you can also save that separately and "assign" it to the transition using .attrTween().

Answer 2

I thought I would add that I opened an issue for this question on the d3 GitHub, and Mr. Bostock suggested using transition.call() to apply the settings in a callback right before using the transition.
The code would look something like this:
function myTransitionSettings(transition) {
transition
.duration(100)
.delay(0);
}
// Then later…
d3.transition().call(myTransitionSettings)…
The callback has access to the current transition object, so it can apply the same settings to each new transition that invokes it.