Allow overriding the 'resource' argument of 'fetch' when invoking 'run'.

Author: ghengeveld

README.md

@@ -695,13 +695,20 @@ throw an exception and crash if the promise rejects.
 
 Runs the `deferFn`, passing any arguments provided as an array.
 
-When used with `useFetch`, `run` has a different signature:
+When used with `useFetch`, `run` has several overloaded signatures:
+
+> `function(resource: String | Resource, init: Object | (init: Object) => Object): void`
 
 > `function(init: Object | (init: Object) => Object): void`
 
-This runs the `fetch` request using the provided `init`. If it's an object it will be spread over the default `init`
-(`useFetch`'s 2nd argument). If it's a function it will be invoked with the default `init` and should return a new
-`init` object. This way you can either extend or override the value of `init`, for example to set request headers.
+> `function(event: SyntheticEvent | Event): void`
+
+> `function(): void`
+
+This way you can run the `fetch` request using the provided `resource` and `init`. `resource` can be omitted. If `init`
+is an object it will be spread over the default `init` (`useFetch`'s 2nd argument). If it's a function it will be
+invoked with the default `init` and should return a new `init` object. This way you can either extend or override the
+value of `init`, for example to set request headers.
 
 #### `reload`
 

packages/react-async/src/index.d.ts

@@ -227,6 +227,8 @@ type AsyncInitialWithout<K extends keyof AsyncInitial<T>, T> =
   | Omit<AsyncRejected<T>, K>
 
 type FetchRun<T> = {
+  run(overrideResource: RequestInfo, overrideInit: (init: RequestInit) => RequestInit): void
+  run(overrideResource: RequestInfo, overrideInit: Partial<RequestInit>): void
   run(overrideInit: (init: RequestInit) => RequestInit): void
   run(overrideInit: Partial<RequestInit>): void
   run(ignoredEvent: React.SyntheticEvent): void

packages/react-async/src/useAsync.js

@@ -173,27 +173,31 @@ const parseResponse = (accept, json) => res => {
   return accept === "application/json" ? res.json() : res
 }
 
-const useAsyncFetch = (input, init, { defer, json, ...options } = {}) => {
-  const method = input.method || (init && init.method)
-  const headers = input.headers || (init && init.headers) || {}
+const isResource = value => typeof value === "string" || (typeof value === "object" && value.url)
+
+const useAsyncFetch = (resource, init, { defer, json, ...options } = {}) => {
+  const method = resource.method || (init && init.method)
+  const headers = resource.headers || (init && init.headers) || {}
   const accept = headers["Accept"] || headers["accept"] || (headers.get && headers.get("accept"))
-  const doFetch = (input, init) => globalScope.fetch(input, init).then(parseResponse(accept, json))
+  const doFetch = (resource, init) =>
+    globalScope.fetch(resource, init).then(parseResponse(accept, json))
   const isDefer =
     typeof defer === "boolean" ? defer : ["POST", "PUT", "PATCH", "DELETE"].indexOf(method) !== -1
   const fn = isDefer ? "deferFn" : "promiseFn"
-  const identity = JSON.stringify({ input, init, isDefer })
+  const identity = JSON.stringify({ resource, init, isDefer })
   const state = useAsync({
     ...options,
     [fn]: useCallback(
       (arg1, arg2, arg3) => {
-        const [override, signal] = arg3 ? [arg1[0], arg3.signal] : [undefined, arg2.signal]
-        if (typeof override === "object" && "preventDefault" in override) {
+        const [runArgs, signal] = isDefer ? [arg1, arg3.signal] : [[], arg2.signal]
+        const [runResource, runInit] = isResource(runArgs[0]) ? runArgs : [, runArgs[0]]
+        if (typeof runInit === "object" && "preventDefault" in runInit) {
           // Don't spread Events or SyntheticEvents
-          return doFetch(input, { signal, ...init })
+          return doFetch(runResource || resource, { signal, ...init })
         }
-        return typeof override === "function"
-          ? doFetch(input, { signal, ...override(init) })
-          : doFetch(input, { signal, ...init, ...override })
+        return typeof runInit === "function"
+          ? doFetch(runResource || resource, { signal, ...runInit(init) })
+          : doFetch(runResource || resource, { signal, ...init, ...runInit })
       },
       [identity] // eslint-disable-line react-hooks/exhaustive-deps
     ),

packages/react-async/src/useAsync.spec.js

@@ -203,11 +203,11 @@ describe("useFetch", () => {
     expect(json).toHaveBeenCalled()
   })
 
-  test("calling `run` with a method argument allows to override `init` parameters", () => {
+  test("calling `run` with a callback as argument allows to override `init` parameters", () => {
     const component = (
-      <Fetch input="/test" init={{ method: "POST" }}>
+      <Fetch input="/test" init={{ method: "POST", body: '{"name":"foo"}' }}>
         {({ run }) => (
-          <button onClick={() => run(init => ({ ...init, body: '{"name":"test"}' }))}>run</button>
+          <button onClick={() => run(init => ({ ...init, body: '{"name":"bar"}' }))}>run</button>
         )}
       </Fetch>
     )
@@ -216,22 +216,56 @@ describe("useFetch", () => {
     fireEvent.click(getByText("run"))
     expect(globalScope.fetch).toHaveBeenCalledWith(
       "/test",
-      expect.objectContaining({ method: "POST", signal: abortCtrl.signal, body: '{"name":"test"}' })
+      expect.objectContaining({ method: "POST", signal: abortCtrl.signal, body: '{"name":"bar"}' })
     )
   })
 
   test("calling `run` with an object as argument allows to override `init` parameters", () => {
     const component = (
-      <Fetch input="/test" init={{ method: "POST" }}>
-        {({ run }) => <button onClick={() => run({ body: '{"name":"test"}' })}>run</button>}
+      <Fetch input="/test" init={{ method: "POST", body: '{"name":"foo"}' }}>
+        {({ run }) => <button onClick={() => run({ body: '{"name":"bar"}' })}>run</button>}
       </Fetch>
     )
     const { getByText } = render(component)
     expect(globalScope.fetch).not.toHaveBeenCalled()
     fireEvent.click(getByText("run"))
     expect(globalScope.fetch).toHaveBeenCalledWith(
       "/test",
-      expect.objectContaining({ method: "POST", signal: abortCtrl.signal, body: '{"name":"test"}' })
+      expect.objectContaining({ method: "POST", signal: abortCtrl.signal, body: '{"name":"bar"}' })
+    )
+  })
+
+  test("calling `run` with a url allows to override fetch's `resource` parameter", () => {
+    const component = (
+      <Fetch input="/foo" options={{ defer: true }}>
+        {({ run }) => <button onClick={() => run("/bar")}>run</button>}
+      </Fetch>
+    )
+    const { getByText } = render(component)
+    expect(globalScope.fetch).not.toHaveBeenCalled()
+    fireEvent.click(getByText("run"))
+    expect(globalScope.fetch).toHaveBeenCalledWith(
+      "/bar",
+      expect.objectContaining({ signal: abortCtrl.signal })
+    )
+  })
+
+  test("overriding the `resource` can be combined with overriding `init`", () => {
+    const component = (
+      <Fetch input="/foo" init={{ method: "POST", body: '{"name":"foo"}' }}>
+        {({ run }) => (
+          <button onClick={() => run("/bar", init => ({ ...init, body: '{"name":"bar"}' }))}>
+            run
+          </button>
+        )}
+      </Fetch>
+    )
+    const { getByText } = render(component)
+    expect(globalScope.fetch).not.toHaveBeenCalled()
+    fireEvent.click(getByText("run"))
+    expect(globalScope.fetch).toHaveBeenCalledWith(
+      "/bar",
+      expect.objectContaining({ method: "POST", signal: abortCtrl.signal, body: '{"name":"bar"}' })
     )
   })