Surrogate Pairs Roundtrip

surrogate-pairs.js

(
  (
    str, 
    c = `${str}`.codePointAt(0), 
    p = 0x10000, q = 0x400, r = 0xD800, s = 0xDC00, 
    h = ~~((c-p) / q) + r, l = (c - p) % q + s
  ) => ({
    h, l, 
    c1: c, c2: (h - r) * q + l - s + p 
  })
)('\u{2CAE}')