Fix ReferenceError of eachOf and remove unused function

[suguru03]

Related to #864, #853

This obj is not defined on dist.
But, I think this improvement needs to applied to `lib'.

[megawac]

Hi @suguru03 mind doing this on lib/ (and picking #853 over)

[suguru03]

I tried to fix this to lib, but some test cases are called synchronously.
So, --running is called synchronously and this implementation does not pass.