Requires a plain record and rejects unknown own keys, including symbols and
non-enumerable keys. Does not require allowed keys to exist or validate values.
Numeric allowed keys use their string property names; symbols retain identity.
Accessors are not invoked; Proxy reflection traps may run and their errors propagate.
Requires a plain record and rejects unknown own keys, including symbols and non-enumerable keys. Does not require allowed keys to exist or validate values. Numeric allowed keys use their string property names; symbols retain identity. Accessors are not invoked; Proxy reflection traps may run and their errors propagate.