Gson Kotlin Extensions. I created a few simple extensions for gson to Simplfy any Gson needs.

GsonExtensions.kt

import com.google.gson.Gson
import com.google.gson.GsonBuilder
import com.google.gson.reflect.TypeToken

val gson: Gson = GsonBuilder().create()
val gsonPretty: Gson = GsonBuilder().setPrettyPrinting().create()

inline fun <reified T> T.toJson(prettyPrint : Boolean = false) :String{
    return if(prettyPrint){
        gsonPretty
    }else {
        gson
    }.toJson(this)
}

inline fun <reified T> String.fromJson() : T {
    return gson.fromJson(this,T::class.java)
}

inline fun <reified T> String.fromListJson() : List<T> {
    val listType = object:  TypeToken<List<T>>(){}.type
    return gson.fromJson(this, listType)
}

GsonTests.kt

data class User(val name :String, val username: String)

import org.junit.Test

class GsonTest {

    @Test
    fun `Gson toJson extension works`(){
        val user = User("Aaron","adfleshner")
        val actual = user.toJson()
        println(actual)
        assert(actual is String)
    }

    @Test
    fun `Gson toJson list extension works`(){
        val user = listOf(User("Aaron","adfleshner"))
        val actual = user.toJson()
        println(actual)
        assert(actual is String)
    }

    @Test
    fun `Gson fromJson extension works`(){
        val str = "{\"name\":\"Aaron\",\"username\":\"adfleshner\"}"
        val user = str.fromJson<User>()
        assert(user is User)
    }


    @Test
    fun `Gson fromListJson extension works`(){
        val str = "[{\"name\":\"Aaron\",\"username\":\"adfleshner\"}]"
        val users = str.fromListJson<User>()
        assert(users is List<User>)
    }

}

implementation 'com.google.code.gson:gson:2.10.1'