# reflect2 [](https://sourcegraph.com/github.com/modern-go/reflect2?badge) [](http://godoc.org/github.com/modern-go/reflect2) [](https://travis-ci.org/modern-go/reflect2) [](https://codecov.io/gh/modern-go/reflect2) [](https://goreportcard.com/report/github.com/modern-go/reflect2) [](https://raw.githubusercontent.com/modern-go/reflect2/master/LICENSE) reflect api that avoids runtime reflect.Value cost * reflect get/set interface{}, with type checking * reflect get/set unsafe.Pointer, without type checking * `reflect2.TypeByName` works like `Class.forName` found in java [json-iterator](https://github.com/json-iterator/go) use this package to save runtime dispatching cost. This package is designed for low level libraries to optimize reflection performance. General application should still use reflect standard library. # reflect2.TypeByName ```go // given package is github.com/your/awesome-package type MyStruct struct { // ... } // will return the type reflect2.TypeByName("awesome-package.MyStruct") // however, if the type has not been used // it will be eliminated by compiler, so we can not get it in runtime ``` # reflect2 get/set interface{} ```go valType := reflect2.TypeOf(1) i := 1 j := 10 valType.Set(&i, &j) // i will be 10 ``` to get set `type`, always use its pointer `*type` # reflect2 get/set unsafe.Pointer ```go valType := reflect2.TypeOf(1) i := 1 j := 10 valType.UnsafeSet(unsafe.Pointer(&i), unsafe.Pointer(&j)) // i will be 10 ``` to get set `type`, always use its pointer `*type` # benchmark Benchmark is not necessary for this package. It does nothing actually. As it is just a thin wrapper to make go runtime public. Both `reflect2` and `reflect` call same function provided by `runtime` package exposed by go language. # unsafe safety Instead of casting `[]byte` to `sliceHeader` in your application using unsafe. We can use reflect2 instead. This way, if `sliceHeader` changes in the future, only reflect2 need to be upgraded. reflect2 tries its best to keep the implementation same as reflect (by testing).