Feature : new methods for string

[nvshah]

• String : digits, letters, alphanumeric

[codecov]

Codecov Report

Merging #161 (d704ec1) into master (6465f00) will decrease coverage by 1.46%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master     #161      +/-   ##
==========================================
- Coverage   97.83%   96.37%   -1.47%     
==========================================
  Files          13       13              
  Lines         787      799      +12     
==========================================
  Hits          770      770              
- Misses         17       29      +12     

Impacted Files	Coverage Δ
lib/src/string.dart	84.61% <0.00%> (-15.39%)	⬇️

📣 Codecov can now indicate which changes are the most critical in Pull Requests. Learn more