API: Fix for function based context to run on each request

packages/api/src/__tests__/graphql.test.ts

@@ -45,4 +45,23 @@ describe('graphql createContextHandler', () => {
       callbackWaitsForEmptyEventLoop: false,
     })
   })
+  it('also accepts a promise that resolve dynamic value on each run', async () => {
+    const handler = createContextHandler(async ({ context }) => {
+      return Promise.resolve({ c: context.d * 5 })
+    })
+    // @ts-ignore
+    expect(await handler({ context: { d: 4 } })).toEqual({
+      c: 20,
+      d: 4,
+      callbackWaitsForEmptyEventLoop: false,
+    })
+    // now run same handler again to simulate second request
+    // with different event and context
+    // @ts-ignore
+    expect(await handler({ context: { d: 5 } })).toEqual({
+      c: 25,
+      d: 5,
+      callbackWaitsForEmptyEventLoop: false,
+    })
+  })
 })

packages/api/src/functions/graphql.ts

@@ -47,12 +47,17 @@ export const createContextHandler = (
           : authToken
     }
 
+    // Sets the **global** context object, which can be imported with:
+    // import { context } from '@redwoodjs/api'
     if (typeof userContext === 'function') {
-      userContext = await userContext({ event, context })
+      // if userContext is a function, run that and return just the result
+      const userContextData = await userContext({ event, context })
+      return setContext({
+        ...context,
+        ...userContextData,
+      })
     }
 
-    // Sets the **global** context object, which can be imported with:
-    // import { context } from '@redwoodjs/api'
     return setContext({
       ...context,
       ...userContext,