fix(fetch): respect OpenAPI 3.0 explode default value for query params (#2143)

* fix(fetch): respect OpenAPI 3.0 explode default value for query params

* feat: add override.fetch.explode option for backward compatibility

* fix: make includeHttpResponseReturnType optional in FetchOptions

* docs: move the document to output.md

Author: yamish123

docs/src/pages/reference/configuration/output.md

@@ -960,6 +960,15 @@ Default: `true`
 When using `fetch` for `client` or `httpClient`, the `fetch` response type includes http status for easier processing by the application.
 If you want to return a defined return type instead of an automatically generated return type, set this value to `false`.
 
+##### explode
+
+Type: `Boolean`.
+Default: `false`
+
+By default, the `fetch` client follows the OpenAPI specification for query parameter explode behavior. This means that query parameters will be exploded unless explicitly set to `false` in the OpenAPI schema.
+
+If you want to maintain backward compatibility with the previous behavior (where only parameters with `explode: true` are exploded), you can set this value to `true`.
+
 #### query
 
 Type: `Object`.

packages/core/src/types.ts

@@ -622,7 +622,8 @@ export type SwrOptions = {
 };
 
 export type FetchOptions = {
-  includeHttpResponseReturnType: boolean;
+  includeHttpResponseReturnType?: boolean;
+  explode?: boolean;
 };
 
 export type InputTransformerFn = (spec: OpenAPIObject) => OpenAPIObject;

packages/fetch/src/index.ts

@@ -60,7 +60,11 @@ export const generateRequestFunction = (
   const explodeParameters = parameters.filter((parameter) => {
     const { schema } = resolveRef<ParameterObject>(parameter, context);
 
-    return schema.in === 'query' && schema.explode;
+    if (override.fetch.explode) {
+      return schema.in === 'query' && schema.explode;
+    } else {
+      return schema.in === 'query' && schema.explode !== false;
+    }
   });
 
   const explodeParametersNames = explodeParameters.map((parameter) => {
@@ -114,7 +118,7 @@ ${
 
   const isNdJson = response.contentTypes.some(isContentTypeNdJson);
   const responseTypeName = fetchResponseTypeName(
-    override.fetch.includeHttpResponseReturnType,
+    override.fetch?.includeHttpResponseReturnType,
     isNdJson ? 'Response' : response.definition.success,
     operationName,
   );
@@ -276,7 +280,7 @@ export type ${responseTypeName} = ${compositeName} & {
 };
 
 export const fetchResponseTypeName = (
-  includeHttpResponseReturnType: boolean,
+  includeHttpResponseReturnType: boolean | undefined,
   definitionSuccessResponse: string,
   operationName: string,
 ) => {

packages/orval/src/utils/options.ts

@@ -353,6 +353,7 @@ export const normalizeOptions = async (
           includeHttpResponseReturnType:
             outputOptions.override?.fetch?.includeHttpResponseReturnType ??
             true,
+          explode: outputOptions.override?.fetch?.explode ?? false,
           ...(outputOptions.override?.fetch ?? {}),
         },
         useDates: outputOptions.override?.useDates || false,

packages/swr/src/client.ts

@@ -236,7 +236,7 @@ export const getSwrMutationFetcherOptionType = (
 export const getSwrMutationFetcherType = (
   response: GetterResponse,
   httpClient: OutputHttpClient,
-  includeHttpResponseReturnType: boolean,
+  includeHttpResponseReturnType: boolean | undefined,
   operationName: string,
   mutator?: GeneratorMutator,
 ) => {

packages/swr/src/index.ts

@@ -533,7 +533,7 @@ export const ${swrKeyFnName} = (${queryKeyProps}) => [\`${route}\`${
     const swrMutationFetcherType = getSwrMutationFetcherType(
       response,
       httpClient,
-      override.fetch.includeHttpResponseReturnType,
+      override.fetch?.includeHttpResponseReturnType,
       operationName,
       mutator,
     );