supertypeof

the type of a value including its fusion types

Synopsis

supertypeof(val: any) -> type

Description

The supertypeof function returns the type of its argument val like typeof except that val is not superdefused before its type is computed. For a value whose type includes fusion types, e.g., a value produced by superfuse, the returned type includes the fusion types whereas typeof returns the type of the original value. For any other value, supertypeof is the same as typeof.

supertypeof is useful for testing and debugging since fusion types are otherwise visible only in output with the -fusion flag.

Examples

The type of a superfused value includes its fusion types

# spq
superfuse | values {super:supertypeof(this),type:typeof(this)}
# input
{a:1}
{a:"x",b:2}
# expected output
{super:<{a:fusion(int64|string),b:fusion(int64|missing)}>,type:<{a:int64}>}
{super:<{a:fusion(int64|string),b:fusion(int64|missing)}>,type:<{a:string,b:int64}>}