search-api: Add typename discriminator hack

Since scala-tsi messes up adding the `typename` discriminator we need to
hack around it by adding the fields manually to the variants that does
not get it 🤷

project/Module.scala

@@ -3,7 +3,8 @@ import GithubWorkflowPlugin.autoImport.*
 import com.scalatsi.plugin.ScalaTsiPlugin.autoImport.{
   typescriptExports,
   typescriptGenerationImports,
-  typescriptOutputFile
+  typescriptOutputFile,
+  typescriptTaggedUnionDiscriminator
 }
 import org.scalafmt.sbt.ScalafmtPlugin.autoImport.*
 import org.typelevel.sbt.tpolecat.TpolecatPlugin.autoImport.*
@@ -192,9 +193,10 @@ trait Module {
 
   protected def typescriptSettings(imports: Seq[String], exports: Seq[String]) = {
     Seq(
-      typescriptGenerationImports := imports,
-      typescriptExports           := exports,
-      typescriptOutputFile        := file("./typescript/types-backend") / s"${this.moduleName}.ts"
+      typescriptGenerationImports        := imports,
+      typescriptExports                  := exports,
+      typescriptOutputFile               := file("./typescript/types-backend") / s"${this.moduleName}.ts",
+      typescriptTaggedUnionDiscriminator := Some("typename")
     )
   }
 }

project/searchapi.scala

@@ -43,7 +43,8 @@ object searchapi extends Module {
       "SubjectAggregationsDTO",
       "SubjectAggsInputDTO",
       "GrepSearchInputDTO",
-      "grep.GrepSearchResultsDTO"
+      "grep.GrepSearchResultsDTO",
+      "grep.GrepResultDTO"
     )
   )
 

search-api/src/main/scala/no/ndla/searchapi/model/api/grep/GrepResultDTO.scala

@@ -9,8 +9,14 @@
 package no.ndla.searchapi.model.api.grep
 
 import cats.implicits.*
+import com.scalatsi.TSType.fromCaseClass
+import com.scalatsi.TypescriptType.{TSLiteralString, TSString, TSUnion}
+import com.scalatsi.{TSIType, TSNamedType, TSType}
+import com.scalatsi.dsl.*
 import io.circe.generic.auto.*
 import sttp.tapir.generic.auto.*
+
+import scala.reflect.runtime.universe.*
 import io.circe.syntax.*
 import io.circe.{Decoder, Encoder, Json}
 import no.ndla.language.Language
@@ -29,6 +35,7 @@ import no.ndla.searchapi.model.search.SearchableGrepElement
 import sttp.tapir.Schema
 import sttp.tapir.Schema.annotations.description
 
+import scala.reflect.ClassTag
 import scala.util.{Success, Try}
 
 @description("Information about a single grep search result entry")
@@ -48,9 +55,12 @@ object GrepResultDTO {
     }
     // NOTE: Adding the discriminator field that scala-tsi generates in the typescript type.
     //       Useful for guarding the type of the object in the frontend.
-    json.mapObject(_.add("type", Json.fromString(result.getClass.getSimpleName)))
+    json.mapObject(_.add("typename", Json.fromString(result.getClass.getSimpleName)))
   }
 
+  implicit val s1: Schema["GrepLaererplanDTO"]      = Schema.string
+  implicit val s2: Schema["GrepTverrfagligTemaDTO"] = Schema.string
+
   implicit val decoder: Decoder[GrepResultDTO] = List[Decoder[GrepResultDTO]](
     Decoder[GrepKjerneelementDTO].widen,
     Decoder[GrepKompetansemaalDTO].widen,
@@ -169,9 +179,11 @@ case class GrepKompetansemaalSettDTO(
 ) extends GrepResultDTO
 case class GrepLaererplanDTO(
     code: String,
-    title: TitleDTO
+    title: TitleDTO,
+    typename: "GrepLaererplanDTO" = "GrepLaererplanDTO"
 ) extends GrepResultDTO
 case class GrepTverrfagligTemaDTO(
     code: String,
-    title: TitleDTO
+    title: TitleDTO,
+    typename: "GrepTverrfagligTemaDTO" = "GrepTverrfagligTemaDTO"
 ) extends GrepResultDTO

typescript/types-backend/search-api.ts

@@ -1,6 +1,6 @@
 // DO NOT EDIT: generated file by scala-tsi
 
-export type GrepResultDTO = (IGrepKompetansemaalDTO | IGrepKjerneelementDTO | IGrepLaererplanDTO | IGrepTverrfagligTemaDTO | IGrepKompetansemaalSettDTO)
+export type GrepResultDTO = (IGrepKjerneelementDTO | IGrepKompetansemaalSettDTO | IGrepTverrfagligTemaDTO | IGrepKompetansemaalDTO | IGrepLaererplanDTO)
 
 export type GrepSort = ("-relevance" | "relevance" | "-title" | "title" | "-code" | "code")
 
@@ -122,7 +122,7 @@ export interface IGrepKjerneelementDTO {
   title: ITitleDTO
   description: IDescriptionDTO
   laereplan: IGrepLaererplanDTO
-  type: "GrepKjerneelementDTO"
+  typename: "GrepKjerneelementDTO"
 }
 
 export interface IGrepKompetansemaalDTO {
@@ -132,20 +132,20 @@ export interface IGrepKompetansemaalDTO {
   kompetansemaalSett: IGrepReferencedKompetansemaalSettDTO
   tverrfagligeTemaer: IGrepTverrfagligTemaDTO[]
   kjerneelementer: IGrepReferencedKjerneelementDTO[]
-  type: "GrepKompetansemaalDTO"
+  typename: "GrepKompetansemaalDTO"
 }
 
 export interface IGrepKompetansemaalSettDTO {
   code: string
   title: ITitleDTO
   kompetansemaal: IGrepReferencedKompetansemaalDTO[]
-  type: "GrepKompetansemaalSettDTO"
+  typename: "GrepKompetansemaalSettDTO"
 }
 
 export interface IGrepLaererplanDTO {
   code: string
   title: ITitleDTO
-  type: "GrepLaererplanDTO"
+  typename: "GrepLaererplanDTO"
 }
 
 export interface IGrepReferencedKjerneelementDTO {
@@ -184,6 +184,7 @@ export interface IGrepSearchResultsDTO {
 export interface IGrepTverrfagligTemaDTO {
   code: string
   title: ITitleDTO
+  typename: "GrepTverrfagligTemaDTO"
 }
 
 export interface IGroupSearchResultDTO {