TypeTransformer

Author: j-ibarra

packages/openapi-ts/src/index.ts

@@ -137,6 +137,7 @@ export {
 export { clientPluginHandler } from './plugins/@hey-api/client-core/plugin';
 export type { Client } from './plugins/@hey-api/client-core/types';
 export type { ExpressionTransformer } from './plugins/@hey-api/transformers/expressions';
+export type { TypeTransformer } from './plugins/@hey-api/transformers/types';
 export { definePluginConfig } from './plugins/shared/utils/config';
 export type { DefinePlugin, Plugin } from './plugins/types';
 export { compiler, tsc } from './tsc';

packages/openapi-ts/src/plugins/@hey-api/transformers/index.ts

@@ -1,2 +1,2 @@
 export { defaultConfig, defineConfig } from './config';
-export type { HeyApiTransformersPlugin } from './types';
+export type { HeyApiTransformersPlugin, TypeTransformer } from './types';

packages/openapi-ts/src/plugins/@hey-api/transformers/types.d.ts

@@ -1,6 +1,22 @@
+import type ts from 'typescript';
+
+import type { GeneratedFile } from '../../../generate/file';
+import type { IR } from '../../../ir/types';
 import type { DefinePlugin, Plugin } from '../../types';
 import type { ExpressionTransformer } from './expressions';
 
+/**
+ * Returns the TypeScript type node for a schema with a specific format.
+ * If undefined is returned, the default type will be used.
+ */
+export type TypeTransformer = ({
+  file,
+  schema,
+}: {
+  file: GeneratedFile;
+  schema: IR.SchemaObject;
+}) => ts.TypeNode | undefined;
+
 export type UserConfig = Plugin.Name<'@hey-api/transformers'> & {
   /**
    * Convert long integers into BigInt values?
@@ -31,6 +47,11 @@ export type UserConfig = Plugin.Name<'@hey-api/transformers'> & {
    * Custom transforms to apply to the generated code.
    */
   transformers?: ReadonlyArray<ExpressionTransformer>;
+
+  /**
+   * Custom type transformers that modify the TypeScript types generated.
+   */
+  typeTransformers?: ReadonlyArray<TypeTransformer>;
 };
 
 export type HeyApiTransformersPlugin = DefinePlugin<UserConfig>;

packages/openapi-ts/src/plugins/@hey-api/typescript/plugin.ts

@@ -401,6 +401,17 @@ const schemaTypeToIdentifier = ({
   schema: IR.SchemaObject;
   state: PluginState;
 }): ts.TypeNode => {
+  const transformersPlugin = plugin.getPlugin('@hey-api/transformers');
+  if (transformersPlugin?.config.typeTransformers) {
+    for (const typeTransformer of transformersPlugin.config.typeTransformers) {
+      const file = plugin.context.file({ id: typesId })!;
+      const typeNode = typeTransformer({ file, schema });
+      if (typeNode) {
+        return typeNode;
+      }
+    }
+  }
+
   switch (schema.type as Required<IR.SchemaObject>['type']) {
     case 'array':
       return arrayTypeToIdentifier({