6bit-encoder.js
function decode4(s) {
  assert.equal(s.length, 4)
  const [ upper, belowUpper, aboveLower, lower ] = s
  return (decode(upper) << 18) | (decode(belowUpper) << 12)
    | (decode(aboveLower) << 6) | decode(lower)
}
function decode4(s) {
  assert.equal(s.length, 4)
  const [ upper, belowUpper, aboveLower, lower ] = s
  return (decode(upper) << 18) | (decode(belowUpper) << 12)
    | (decode(aboveLower) << 6) | decode(lower)
}
function decode4 ( s ) { assert . equal ( s . length , 4 ) const [ upper , belowUpper , aboveLower , lower ] = s return ( decode ( upper ) << 18 ) | ( decode ( belowUpper ) << 12 ) | ( decode ( aboveLower ) << 6 ) | decode ( lower ) }
Decodes four chars into an 24 bit number

@name decode4

@param {String} s the chars to decode
@returns {Number} a 24 bit number
Decodes four chars into an 24 bit number