Scala TSI can automatically generate Typescript Interfaces from your Scala classes.
To use the project add the SBT plugin dependency in project/plugins.sbt:
// See badge above for latest version number
addSbtPlugin("com.scalatsi" % "sbt-scala-tsi" % "0.3.0")And configure the plugin in your project:
// Replace with your project definition
lazy val root = (project in file("."))
.settings(
// The classes that you want to generate typescript interfaces for
typescriptClassesToGenerateFor := Seq("MyClass"),
// The output file which will contain the typescript interfaces
typescriptOutputFile := baseDirectory.value / "model.ts",
// Include the package(s) of the classes here
// Optionally import your own TSType implicits to override default default generated
typescriptGenerationImports := Seq("mymodel._", "MyTypescript._")
)Now sbt generateTypescript will transform a file like
case class MyClass(foo: String, bar: Int)Into a typescript interface like
export interface IMyClass {
foo: string
bar: number
}See #Example or the example project for more a more examples
Currently, scala-tsi enter an infinte loop if you have not specified implicits and have circular references in your models. You will get an error like:
[error] java.lang.StackOverflowError
[error] scala.tools.nsc.typechecker.Contexts$Context.nextOuter(Contexts.scala:809)
// The above will repeat a lot
You will have to manually define on of the models to break the ciruclar reference.
| Key | Type | Default | Description |
|---|---|---|---|
| typescriptClassesToGenerateFor | Seq[String] | Seq() |
A list of all your (top-level) classes that you want to generate interfaces for |
| typescriptGenerationImports | Seq[String] | Seq() |
A list of all imports. This should import all classes you defined above, as well as custom TSType implicits |
| typescriptOutputFile | File | target/scala-interfaces.ts |
The output file with generated typescript interfaces |
| typescriptStyleSemicolons | Boolean | false |
Whether to add booleans to the exported model (experimental) |
You can check out the example project for a complete set-up and more examples.
Say we have the following JSON:
{
"name": "person name",
"email": "abc@example.org",
"age": 25,
"job": {
"tasks": ["Be in the office", "Drink coffee"],
"boss": "Johnson"
}
}Generated from this Scala domain model:
package myproject
case class Person(
name: String,
email: Email,
age: Option[Int],
// for privacy reasons, we do not put this social security number in the JSON
ssn: Option[Int],
job: Job
)
// This type will get erased when serializing to JSON, only the string remains
case class Email(address: String)
case class Job(tasks: Seq[String], boss: String)
With Typescript, your frontend can know what data is available in what format. However, keeping the Typescript definitions in sync with your scala classes is a pain and error-prone. scala-tsi solves that.
First we define the mapping as follows
package myproject
import com.scalatsi._
import com.scalatsi.dsl._
// A TSType[T] is what tells scala-tsi how to convert your type T into typescript
// MyModelTSTypes contains all TSType[_]'s for your model
// You can also spread these throughout your codebase, for example in the same place where your JSON (de)serializers
object MyModelTSTypes extends DefaultTSTypes {
// Tell scala-tsi to use the typescript type of string whenever we have an Email type
// Alternatively, TSType.alias[Email, String] will create a `type Email = string` entry in the typescript file
implicit val tsEmail = TSType.sameAs[Email, String]
// TSType.fromCaseClass will convert your case class to a typescript definition
// `- ssn` indicated the ssn field should be removed
implicit val tsPerson = TSType.fromCaseClass[Person] - "ssn"
}And in your build.sbt configure the sbt plugin to output your class:
lazy val root = (project in file("."))
.settings(
typescriptClassesToGenerateFor := Seq("Person"),
typescriptGenerationImports := Seq("myproject._", "MyModelTSTypes._"),
typescriptOutputFile := baseDirectory.value / "model.ts"
)
this will generate in your project root a model.ts:
export interface IPerson {
name : string
email : string
age ?: number
job: IJob
}
export interface IJob {
tasks: string[]
boss: string
}
This document contains more detailed explanation of the library and usage
See this list for an overview of completed features, and issues for open feature ideas.