highSurrogate
Returns the leading surrogate (a high surrogate code unit) of the surrogate pair representing the specified supplementary character (Unicode code point) in the UTF-16 encoding. If the specified character is not a Character.html#supplementary, an unspecified char is returned.
If .isSupplementaryCodePoint is true, then .isHighSurrogate(highSurrogate(x)) and .toCodePoint(highSurrogate(x), .lowSurrogate(x)) == x are also always true.
Return
the leading surrogate code unit used to represent the character in the UTF-16 encoding
Since
1.7
Parameters
codePoint
a supplementary character (Unicode code point)