Fix adding to list asynchronously

[ohjann]

Fixes #569

[javve]

Thanks for the PR, however, I'm not sure that I understand what the problem is? :/
Is it possible to show in a test?

[codecov-io]

Codecov Report

Merging #570 (30967fa) into master (572cc95) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #570   +/-   ##
=======================================
  Coverage   94.56%   94.56%           
=======================================
  Files          19       19           
  Lines         810      810           
  Branches      188      188           
=======================================
  Hits          766      766           
  Misses         31       31           
  Partials       13       13           

Impacted Files	Coverage Δ
src/index.js	98.78% <100.00%> (ø)

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[javve]

Ahhh, now I get it!
I added a test to confirm this as well: 000150a

Thanks!

[ohjann]

@javve sorry should've provided more context two years ago lol