--- /dev/null
+import type {CodeKeywordDefinition, KeywordErrorDefinition} from "../../types"
+import type {KeywordCxt} from "../../compile/validate"
+import {_, not, getProperty, Name} from "../../compile/codegen"
+import {checkMetadata} from "./metadata"
+import {checkNullableObject} from "./nullable"
+import {typeErrorMessage, typeErrorParams, _JTDTypeError} from "./error"
+import {DiscrError, DiscrErrorObj} from "../discriminator/types"
+
+export type JTDDiscriminatorError =
+ | _JTDTypeError<"discriminator", "object", string>
+ | DiscrErrorObj<DiscrError.Tag>
+ | DiscrErrorObj<DiscrError.Mapping>
+
+const error: KeywordErrorDefinition = {
+ message: (cxt) => {
+ const {schema, params} = cxt
+ return params.discrError
+ ? params.discrError === DiscrError.Tag
+ ? `tag "${schema}" must be string`
+ : `value of tag "${schema}" must be in mapping`
+ : typeErrorMessage(cxt, "object")
+ },
+ params: (cxt) => {
+ const {schema, params} = cxt
+ return params.discrError
+ ? _`{error: ${params.discrError}, tag: ${schema}, tagValue: ${params.tag}}`
+ : typeErrorParams(cxt, "object")
+ },
+}
+
+const def: CodeKeywordDefinition = {
+ keyword: "discriminator",
+ schemaType: "string",
+ implements: ["mapping"],
+ error,
+ code(cxt: KeywordCxt) {
+ checkMetadata(cxt)
+ const {gen, data, schema, parentSchema} = cxt
+ const [valid, cond] = checkNullableObject(cxt, data)
+
+ gen.if(cond)
+ validateDiscriminator()
+ gen.elseIf(not(valid))
+ cxt.error()
+ gen.endIf()
+ cxt.ok(valid)
+
+ function validateDiscriminator(): void {
+ const tag = gen.const("tag", _`${data}${getProperty(schema)}`)
+ gen.if(_`${tag} === undefined`)
+ cxt.error(false, {discrError: DiscrError.Tag, tag})
+ gen.elseIf(_`typeof ${tag} == "string"`)
+ validateMapping(tag)
+ gen.else()
+ cxt.error(false, {discrError: DiscrError.Tag, tag}, {instancePath: schema})
+ gen.endIf()
+ }
+
+ function validateMapping(tag: Name): void {
+ gen.if(false)
+ for (const tagValue in parentSchema.mapping) {
+ gen.elseIf(_`${tag} === ${tagValue}`)
+ gen.assign(valid, applyTagSchema(tagValue))
+ }
+ gen.else()
+ cxt.error(
+ false,
+ {discrError: DiscrError.Mapping, tag},
+ {instancePath: schema, schemaPath: "mapping", parentSchema: true}
+ )
+ gen.endIf()
+ }
+
+ function applyTagSchema(schemaProp: string): Name {
+ const _valid = gen.name("valid")
+ cxt.subschema(
+ {
+ keyword: "mapping",
+ schemaProp,
+ jtdDiscriminator: schema,
+ },
+ _valid
+ )
+ return _valid
+ }
+ },
+}
+
+export default def