feat: throw error for invalid extended input

[peaceiris]

• test: Add invalid case

[codecov]

Codecov Report

Merging #387 into main will decrease coverage by 0.79%.
The diff coverage is 50.00%.

@@             Coverage Diff             @@
##              main     #387      +/-   ##
===========================================
- Coverage   100.00%   99.20%   -0.80%     
===========================================
  Files            6        6              
  Lines          124      126       +2     
  Branches        14       15       +1     
===========================================
+ Hits           124      125       +1     
- Misses           0        1       +1     

Impacted Files	Coverage Δ
src/get-url.ts	93.33% <50.00%> (-6.67%)	⬇️

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