docs(readme): improve node API usage

[gregberge]

Fix #20

[codecov]

Codecov Report

Merging #21 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #21   +/-   ##
=======================================
  Coverage   42.66%   42.66%           
=======================================
  Files          19       19           
  Lines         150      150           
  Branches       32       32           
=======================================
  Hits           64       64           
  Misses         69       69           
  Partials       17       17

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