[Refactor] use globalThis if available

[JounQin]

@ljharb

Like inspect-js/available-typed-arrays#13

[codecov]

Codecov Report

Merging #52 (d4f250c) into main (c1b83ea) will not change coverage.
The diff coverage is 100.00%.

❗ Current head d4f250c differs from pull request most recent head 2a16d1f. Consider uploading reports for the commit 2a16d1f to get more accurate results

@@            Coverage Diff            @@
##              main       #52   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            1         1           
  Lines           35        36    +1     
  Branches         8         9    +1     
=========================================
+ Hits            35        36    +1     

Impacted Files	Coverage Δ
index.js	100.00% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update c1b83ea...2a16d1f. Read the comment docs.