Experimental library enabling JSON5 serialization and deserialization with support for polymorphic types, class discriminators, comment serialization, concise error messages, and duplicate key rejection.
This is an experimental JSON5 library for Kotlin/JVM and Kotlin/Native. It makes use of the kotlinx.serialization framework to serialize object hierarchies into standard-compliant JSON5 text and vice versa.
json5k is available on Maven Central:
plugins {
kotlin("jvm") version "1.8.10"
kotlin("plugin.serialization") version "1.8.10"
}
repositories {
mavenCentral()
}
dependencies {
implementation("io.github.xn32:json5k:0.3.0")
}
Official versions are published for the following targets:
jvmlinuxX64, macosX64, iosX64, mingwX64Snapshot versions of the main branch are available from here.
@SerialName annotationsimport io.github.xn32.json5k.Json5
import kotlinx.serialization.SerialName
kotlinx.serialization.Serializable
kotlinx.serialization.decodeFromString
kotlinx.serialization.encodeToString
( int: )
Json5.encodeToString(IntWrapper())
Json5.decodeFromString<IntWrapper>()
Json5.decodeFromString<IntWrapper>()
Running this code will produce the following output:
{
// First day of the event
date: "2022-10-04",
// Registered attendees
attendees: [
{
name: "Emma",
age: 31
}
]
}
Control generated JSON5 output as follows:
import io.github.xn32.json5k.Json5
import kotlinx.serialization.Serializable
import kotlinx.serialization.encodeToString
val json5 = Json5 {
prettyPrint = true
indentationWidth = 2
useSingleQuotes = true
quoteMemberNames = true
encodeDefaults = true
}
@Serializable
data class ( name: String, age: UInt? = )
println(json5.encodeToString(Person()))
This will result in the following output:
{
'name': 'Oliver',
'age': null
}
See the unit tests for serialization and deserialization for more examples.
macosArm64iosArm64iosSimulatorArm64import io.github.xn32.json5k.Json5
import kotlinx.serialization.decodeFromString
import kotlinx.serialization.encodeToString
// Serialization:
Json5.encodeToString(5142) // 5142
Json5.encodeToString(listOf(4.5, 1.5e2, 1.2e15)) // [4.5,150.0,1.2E15]
Json5.encodeToString(mapOf("a" to 10, "b" to 20)) // {a:10,b:20}
Json5.encodeToString(Double.NEGATIVE_INFINITY) // -Infinity
Json5.encodeToString<Int?>(null) // null
// Deserialization:
Json5.decodeFromString<Int?>("113") // 113
Json5.decodeFromString<List<Double>>("[1.2, .4]") // [1.2, 0.4]
Json5.decodeFromString<Map<String, Int>>("{ a: 10, 'b': 20, }") // {a=10, b=20}
Json5.decodeFromString<Double>("+Infinity") // Infinity
Json5.decodeFromString<Int?>("null") // null
// Deserialization errors:
Json5.decodeFromString<Byte>("190")
// UnexpectedValueError: signed integer in range [-128..127] expected at position 1:1
Json5.decodeFromString<List<Double>>("[ 1.0,,")
// CharError: unexpected character ',' at position 1:7
import io.github.xn32.json5k.Json5
import kotlinx.serialization.Serializable
import kotlinx.serialization.decodeFromString
import kotlinx.serialization.encodeToString
data class Person(val name: String, val age: UInt? = null)
// Serialization:
Json5.encodeToString(Person("John", 31u)) // {name:"John",age:31}
Json5.encodeToString(Person("Jane")) // {name:"Jane"}
// Deserialization:
Json5.decodeFromString<Person>("{ name: 'Carl' }") // Person(name=Carl, age=null)
Json5.decodeFromString<Person>("{ name: 'Carl', age: 42 }") // Person(name=Carl, age=42)
// Deserialization errors:
Json5.decodeFromString<Person>("{ name: 'Carl', age: 42, age: 10 }")
// DuplicateKeyError: duplicate key 'age' at position 1:26
import io.github.xn32.json5k.ClassDiscriminator
import io.github.xn32.json5k.Json5
import kotlinx.serialization.SerialName
import kotlinx.serialization.Serializable
import kotlinx.serialization.decodeFromString
import kotlinx.serialization.encodeToString
sealed interface Producer
data class NumberProducer(val init: UInt) : Producer
// Serialization:
Json5.encodeToString<Producer>(NumberProducer(10u)) // {mode:"numbers",init:10}
// Deserialization:
Json5.decodeFromString<Producer>("{ init: 0, mode: 'numbers' }") // NumberProducer(init=0)
// Deserialization errors:
Json5.decodeFromString<Producer>("{ init: 0 }")
// MissingFieldError: missing field 'mode' in object at position 1:1
import io.github.xn32.json5k.Json5
import io.github.xn32.json5k.SerialComment
import kotlinx.serialization.Serializable
import kotlinx.serialization.encodeToString
data class Person(
val name: String,
val age: UInt? = null
)
data class Event(
val date: String,
val attendees: List<Person>
)
val json5 = Json5 {
prettyPrint = true
}
println(
json5.encodeToString(
Event("2022-10-04", listOf(Person("Emma", 31u)))
)
)
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