int getInt16(int byteOffset, [ Endianness endian = Endianness.BIG_ENDIAN ])

Returns the (possibly negative) integer represented by the two bytes at the specified byteOffset in this object, in two's complement binary form.

The return value will be between -215 and 215 - 1, inclusive.

Throws RangeError if byteOffset is negative, or byteOffset + 2 is greater than the length of this object.

Source 

int getInt16(int byteOffset, [Endianness endian = Endianness.BIG_ENDIAN]);