fix: compatibility with named export and es5

[alexander-akait]

This PR contains a:

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

Motivation / Use-Case

fixes #749

Breaking Changes

No

Additional Info

No

[codecov]

Codecov Report

Merging #751 (79b44f1) into master (e0d834d) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #751   +/-   ##
=======================================
  Coverage   89.27%   89.27%           
=======================================
  Files           6        6           
  Lines         802      802           
  Branches      247      247           
=======================================
  Hits          716      716           
  Misses         83       83           
  Partials        3        3           

Impacted Files	Coverage Δ
src/loader.js	90.36% <100.00%> (ø)

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