fix: respect externals

[alexander-akait]

This PR contains a:

• bugfix
• new feature
• code refactor
• test update
• typo fix
• metadata update

Motivation / Use-Case

fixes #95

Breaking Changes

No

Additional Info

No

[codecov]

Codecov Report

Merging #264 into master will decrease coverage by 3.20%.
The diff coverage is 46.15%.

@@            Coverage Diff             @@
##           master     #264      +/-   ##
==========================================
- Coverage   78.57%   75.36%   -3.21%     
==========================================
  Files           6        6              
  Lines         126      138      +12     
  Branches       41       46       +5     
==========================================
+ Hits           99      104       +5     
- Misses         25       29       +4     
- Partials        2        5       +3     

Impacted Files	Coverage Δ
src/utils.js	78.12% <30.00%> (-21.88%)	⬇️
src/index.js	94.73% <100.00%> (+0.29%)	⬆️

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