Protect against an undefined command target

[lee-dohm]

Description of the Change

Protects against an undefined command target in the CommandLogger.

Alternate Designs

• Considered fixing bug that was causing target to be undefined but figured that this code should be more flexible than that

Benefits

• Prevents uncaught exceptions like in Uncaught TypeError: Cannot read property 'nodeName' of undefined #135

Possible Drawbacks

• Doesn't address how something is calling a command on an undefined target

Applicable Issues

Fixes #135

[lee-dohm]

/cc @50Wliu since you pointed this out to me 😀

[winstliu]

It looks like these get used further down the line, such as here. Maybe an alternate design would be to throw early when adding a command without a target?

[lee-dohm]

Yeah, good point. I may go back to my original idea and just return if there isn't a target. I'm going to write some tests around all of this too.