feat(plantae): respect json type of original request body (#34)

Author: orionmiz

.changeset/wicked-rice-switch.md

@@ -0,0 +1,5 @@
+---
+"plantae": patch
+---
+
+feat(plantae): respect json type of original request body

packages/plantae/src/axios/createAxiosInterceptors.spec.ts

@@ -508,4 +508,54 @@ describe("createAxiosInterceptors", () => {
 
     expect(res.data).toBe("retried");
   });
+
+  it("should respect json type of original request body", async () => {
+    server.use(
+      http.post(base("/"), () => {
+        return new Response();
+      })
+    );
+
+    const axios = Axios.create({
+      baseURL,
+    });
+
+    const { request } = createAxiosInterceptors({
+      client: axios,
+      plugins: [
+        {
+          name: "plugin-modify-body",
+          hooks: {
+            beforeRequest: async (req) => {
+              return new Request(req, {
+                body: JSON.stringify({ ...(await req.json()), modified: true }),
+              });
+            },
+          },
+        },
+      ],
+    });
+
+    let type: string | undefined;
+    let data: any;
+
+    axios.interceptors.request.use((config) => {
+      type = typeof config.data;
+      data = config.data;
+
+      return config;
+    });
+
+    axios.interceptors.request.use(request.onFulfilled, request.onRejected);
+
+    await axios.post("/", {
+      foo: "bar",
+    });
+
+    expect(type).toBe("object");
+    expect(data).toEqual({
+      foo: "bar",
+      modified: true,
+    });
+  });
 });

packages/plantae/src/axios/createAxiosInterceptors.ts

@@ -69,13 +69,17 @@ async function extendClientRequest(
 ): Promise<InternalAxiosRequestConfig> {
   let data = clientRequest.data;
 
+  const isJSONBody = typeof data === "object" && data !== null;
+
   const { headers } = adapterRequest;
 
   const contentType = headers.get("Content-Type");
 
   if (adapterRequest.body) {
     if (contentType?.includes("multipart/form-data")) {
       data = await adapterRequest.formData();
+    } else if (contentType?.includes("application/json") && isJSONBody) {
+      data = await adapterRequest.json();
     } else if (
       contentType?.includes("application/x-www-form-urlencoded") ||
       contentType?.includes("text/plain") ||