fix: ignore modules without identifier

[alexander-akait]

This PR contains a:

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

Motivation / Use-Case

fixes #205

Breaking Changes

No

Additional Info

there may edge cases, feel free to open a new issue, if you faced with this problem

[codecov]

Codecov Report

Merging #627 into master will increase coverage by 0.21%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #627      +/-   ##
==========================================
+ Coverage   88.74%   88.96%   +0.21%     
==========================================
  Files          10       10              
  Lines         613      616       +3     
  Branches      160      161       +1     
==========================================
+ Hits          544      548       +4     
+ Misses         66       65       -1     
  Partials        3        3              

Impacted Files	Coverage Δ
src/loader.js	91.89% <100.00%> (+1.15%)	⬆️

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