Go: map[string]interface{} vs map[string]string

mapvaluetypes.go

package mem

import "testing"

// So if you're encoding small types (i.e. for JSON on the fly) there is a difference.
//
// maptypes$ go test -bench=. -benchtime=20s
// testing: warning: no tests to run
// PASS
// Benchmark_MapStringInterface	20000000	      1407 ns/op	     352 B/op	       3 allocs/op
// Benchmark_MapStringString	  20000000	      1130 ns/op	     336 B/op	       2 allocs/op
// ok  	test/mem/maptypes	54.116s
//

func Benchmark_MapStringInterface(b *testing.B) {
    b.ReportAllocs()
    b.ResetTimer()
    for i := 0; i < b.N; i++ {
        _ = map[string]interface{}{
            "hello": "foo",
        }
    }
}

func Benchmark_MapStringString(b *testing.B) {
    b.ReportAllocs()
    b.ResetTimer()
    for i := 0; i < b.N; i++ {
        _ = map[string]string{
            "hello": "foo",
        }
    }
}