Function JSStringGetLength 

pub unsafe extern "C-unwind" fn JSStringGetLength(
    string: JSStringRef,
) -> usize

Available on crate features JSBase and JSStringRef only.

Returns the number of Unicode characters in a JavaScript string.

Parameter string: The JSString whose length (in Unicode characters) you want to know.

Returns: The number of Unicode characters stored in string.

Safety

string must be a valid pointer.