fix: fixed to be compatible with Flutter for Web (#8)

[myConsciousness]

Hi,

I implemented one solution mentioned in #7. However, I am not a very expert in this field, so perhaps the elimination of the mask operation may cause problem with the standard specifications. Please verify this point.

But at least my assumption was that if we guarantee the value of value variable as the maximum number within the allowable range of JavaScript, the mask operation would be unnecessary.

[LuchoTurtle]

Thanks for opening this issue!
I've looked at the changes you've made and they look fine to me! So they should be mergeable straight away. This code should correctly encode positive integers within the safe range supported by JavaScript as varints.

I was torn between doing something as you've done and using BigInt to represent this value, all the while also being compilable to 53-bit integers in JS. I implemented it with the masking because I wanted to have it more "generalized", but completely forgot about the JS bit constraint. If we wanted to encode integers that are larger than the safe integer range, we'd need to use BigInt, even with its performance cost. This is the "safer" option and will allow us to encode correctly any integer value, regardless of its size.

Since your code checks that the input value is within the safe integer range supported by JS and guaranteed to be non-negative, we know that the sign bit of the shifted value will always be 0, so no masking (&) is needed. This makes perfect sense.

I'll approve this PR and merge it.
Thank you! 😍

[codecov]

Codecov Report

Merging #8 (5f9ab99) into main (21f74dd) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##              main        #8   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            4         4           
  Lines           54        57    +3     
=========================================
+ Hits            54        57    +3     

Impacted Files	Coverage Δ
lib/src/multihash/varint_utils.dart	100.00% <100.00%> (ø)

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[nelsonic]

Thanks. 🙏