From 63e1905b00fb83377803b9e81179af1031e1c8f8 Mon Sep 17 00:00:00 2001
From: Harry Brundage <harry.brundage@gmail.com>
Date: Sun, 25 Jun 2023 22:21:48 -0400
Subject: [PATCH] Add a useApi hook for accessing the current api client
 without having a reference to it

---
 packages/react/spec/GadgetProvider.spec.tsx | 26 ++++++++++++++-
 packages/react/src/GadgetProvider.tsx       | 37 +++++++++++++++++++--
 2 files changed, 59 insertions(+), 4 deletions(-)

diff --git a/packages/react/spec/GadgetProvider.spec.tsx b/packages/react/spec/GadgetProvider.spec.tsx
index f8384461d..ab88658e8 100644
--- a/packages/react/spec/GadgetProvider.spec.tsx
+++ b/packages/react/spec/GadgetProvider.spec.tsx
@@ -4,7 +4,7 @@ import { GadgetConnection } from "@gadgetinc/api-client-core";
 import { renderHook } from "@testing-library/react";
 import type { ReactNode } from "react";
 import React from "react";
-import { Provider, useConnection } from "../src/GadgetProvider";
+import { Provider, useApi, useConnection } from "../src/GadgetProvider";
 import { mockUrqlClient } from "./testWrapper";
 
 describe("GadgetProvider", () => {
@@ -37,6 +37,16 @@ describe("GadgetProvider", () => {
     expect(result).toBeTruthy();
   });
 
+  test("internal components can access the api client when wrapped in the provider which is passed an api client", () => {
+    const { result } = renderHook(() => useApi(), {
+      wrapper: (props: { children: ReactNode }) => {
+        return <Provider api={mockApiClient}>{props.children}</Provider>;
+      },
+    });
+
+    expect(result.current).toBe(mockApiClient);
+  });
+
   test("the provider errors when not passed anything", () => {
     expect(() =>
       renderHook(() => useConnection(), {
@@ -62,4 +72,18 @@ describe("GadgetProvider", () => {
       `"Invalid Gadget API client passed to <Provider /> component -- please pass an instance of your generated client, like <Provider api={api} />!"`
     );
   });
+
+  test("internal components can't access the api client when wrapped in the provider which is passed an urql client", () => {
+    expect(() =>
+      renderHook(() => useApi(), {
+        wrapper: (props: { children: ReactNode }) => {
+          return <Provider value={mockUrqlClient}>{props.children}</Provider>;
+        },
+      })
+    ).toThrowErrorMatchingInlineSnapshot(`
+      "useApi hook called in context with deprecated <Provider/> convention. Please ensure you are wrapping this hook with the <Provider/> component from @gadgetinc/react and passing it an instance of your api client, like <Provider api={api} />.
+
+              The <Provider /> component is currently being passed a value, like <Provider value={api.connection.currentClient}/>. Please update this to <Provider api={api} />."
+    `);
+  });
 });
diff --git a/packages/react/src/GadgetProvider.tsx b/packages/react/src/GadgetProvider.tsx
index 385656b19..644b149e3 100644
--- a/packages/react/src/GadgetProvider.tsx
+++ b/packages/react/src/GadgetProvider.tsx
@@ -1,7 +1,6 @@
 import type { AnyClient, GadgetConnection } from "@gadgetinc/api-client-core";
 import { $gadgetConnection, isGadgetClient } from "@gadgetinc/api-client-core";
-import type { ReactNode } from "react";
-import React from "react";
+import React, { ReactNode, useContext } from "react";
 import type { Client as UrqlClient } from "urql";
 import { Provider as UrqlProvider } from "urql";
 
@@ -89,8 +88,12 @@ export function Provider(props: ProviderProps | DeprecatedProviderProps) {
   );
 }
 
+/**
+ * Get the current `GadgetConnection` object from React context.
+ * Must be called within a component wrapped by the `<Provider api={...} />` component.
+ **/
 export const useConnection = () => {
-  const urqlClient = React.useContext(GadgetUrqlClientContext);
+  const urqlClient = useContext(GadgetUrqlClientContext);
   if (!urqlClient) {
     throw new Error("No urql client object in React context, have you added the <Provider/> wrapper component from @gadgetinc/react?");
   }
@@ -108,3 +111,31 @@ export const useConnection = () => {
 
   return connection;
 };
+
+/**
+ * Get the current `api` object from React context
+ * Must be called within a component wrapped by the `<Provider api={...} />` component.
+ **/
+export const useApi = () => {
+  const api = useContext(GadgetClientContext);
+  const urqlClient = useContext(GadgetUrqlClientContext);
+  if (!api) {
+    if (urqlClient) {
+      throw new Error(
+        `useApi hook called in context with deprecated <Provider/> convention. Please ensure you are wrapping this hook with the <Provider/> component from @gadgetinc/react and passing it an instance of your api client, like <Provider api={api} />.
+
+        The <Provider /> component is currently being passed a value, like <Provider value={api.connection.currentClient}/>. Please update this to <Provider api={api} />.`
+      );
+    } else {
+      throw new Error(
+        `useApi hook called in context where no Gadget API client is available. Please ensure you are wrapping this hook with the <Provider/> component from @gadgetinc/react.
+      
+      Possible remedies:
+       - ensuring you have the <Provider/> component wrapped around your hook invocation
+       - ensuring you are passing an api client instance to the provider, usually <Provider api={api}>
+       - ensuring your @gadget-client/<your-app> package and your @gadgetinc/react package are up to date`
+      );
+    }
+  }
+  return api;
+};