Stick to version 1.0.2 if need to support node.js <16.15.1. wcwidth.js is a simple javascript porting of wcwidth() implemented in C by Markus Kuhn. wcwidth() and its string version, wcswidth() are defined by IEEE Std 1002.1-2001, a.k.a. POSIX.1-2001, and return the number of columns used to represent a wide character and string on fixed-width output devices like terminals. Markus's implementation