improvement: deferFn and promiseFn now have the same signature.

The `promiseFn` and the `deferFn` have been unified. They now share the
following signature:

```ts
export type AsyncFn<T, C> = (
  context: C | undefined,
  props: AsyncProps<T, C>,
  controller: AbortController
) => Promise<T>
```

Before the `deferFn` and `promiseFn` had this signature:

```ts
export type PromiseFn<T> = (props: AsyncProps<T>, controller: AbortController) => Promise<T>

export type DeferFn<T> = (
  args: any[],
  props: AsyncProps<T>,
  controller: AbortController
) => Promise<T>
```

The big change is the introduction of the `context` parameter. The idea
behind this parameter is that it will contain the parameters which are
not known to `AsyncOptions` for use in the `promiseFn` and `asyncFn`.

Another goal of this commit is to make TypeScript more understanding
of the `context` which `AsyncProps` implicitly carries around. Before
this commit the `AsyncProps` accepted extra prop via `[prop: string]: any`.
This breaks TypeScript's understanding of the divisions somewhat. This
also led to missing types for `onCancel` and `suspense`, which have been
added in this commit.

To solve this we no longer allow random extra properties that are unknown
to `AsyncProps`. Instead only the new `context` of `AsyncProps` is passed.
This means that the `[prop: string]: any` of `AsyncProps` is removed this
makes TypeScript understand the props better.

The other big change of this commit that `useAsync` no longer supports
an overload. This means that the user can no longer do:

```ts
const state = useAsync(loadPlayer, { context: { playerId: 1 } })
```

But have to be more explicit:

```t
const state = useAsync({ promiseFn: loadPlayer, context: { playerId: 1 } })
```

These changes are of course a breaking change.

Also now compiling TypeScript on `yarn test` this should prevent type
errors from slipping in.

Closes: async-library#246

WIP: Trying to fix build

asdf

.gitignore

@@ -15,3 +15,5 @@ lerna-debug.log*
 # when working with contributors
 package-lock.json
 yarn.lock
+
+.vscode

.travis.yml

@@ -8,3 +8,6 @@ cache:
 script: yarn && yarn ci
 after_success:
   - bash <(curl -s https://codecov.io/bash) -e TRAVIS_NODE_VERSION
+before_install:
+  - curl -o- -L https://yarnpkg.com/install.sh | bash -s -- --version 1.21.1
+  - export PATH="$HOME/.yarn/bin:$PATH"

docs/api/options.md

@@ -5,6 +5,7 @@ These can be passed in an object to `useAsync(options)`, or as props to `<Async
 - [`promise`](#promise) An already started Promise instance.
 - [`promiseFn`](#promisefn) Function that returns a Promise, automatically invoked.
 - [`deferFn`](#deferfn) Function that returns a Promise, manually invoked with `run`.
+- [`context`](#context) The first argument for the `promise` and `promiseFn` function.
 - [`watch`](#watch) Watch a value and automatically reload when it changes.
 - [`watchFn`](#watchfn) Watch this function and automatically reload when it returns truthy.
 - [`initialValue`](#initialvalue) Provide initial data or error for server-side rendering.
@@ -31,17 +32,17 @@ A Promise instance which has already started. It will simply add the necessary r
 
 ## `promiseFn`
 
-> `function(props: Object, controller: AbortController): Promise`
+> `function(context C, props: AsyncOptions, controller: AbortController): Promise`
 
 A function that returns a promise. It is automatically invoked in `componentDidMount` and `componentDidUpdate`. The function receives all component props \(or options\) and an AbortController instance as arguments.
 
-> Be aware that updating `promiseFn` will trigger it to cancel any pending promise and load the new promise. Passing an inline (arrow) function will cause it to change and reload on every render of the parent component. You can avoid this by defining the `promiseFn` value **outside** of the render method. If you need to pass variables to the `promiseFn`, pass them as additional props to `<Async>`, as `promiseFn` will be invoked with these props. Alternatively you can use `useCallback` or [memoize-one](https://github.com/alexreardon/memoize-one) to avoid unnecessary updates.
+> Be aware that updating `promiseFn` will trigger it to cancel any pending promise and load the new promise. Passing an inline (arrow) function will cause it to change and reload on every render of the parent component. You can avoid this by defining the `promiseFn` value **outside** of the render method. If you need to pass variables to the `promiseFn`, pass them via the `context` props of `<Async>`, as `promiseFn` will be invoked with these props. Alternatively you can use `useCallback` or [memoize-one](https://github.com/alexreardon/memoize-one) to avoid unnecessary updates.
 
 ## `deferFn`
 
-> `function(args: any[], props: Object, controller: AbortController): Promise`
+> `function(context: C, props: AsyncOptions, controller: AbortController): Promise`
 
-A function that returns a promise. This is invoked only by manually calling `run(...args)`. Receives the same arguments as `promiseFn`, as well as any arguments to `run` which are passed through as an array. The `deferFn` is commonly used to send data to the server following a user action, such as submitting a form. You can use this in conjunction with `promiseFn` to fill the form with existing data, then updating it on submit with `deferFn`.
+A function that returns a promise. This is invoked only by manually calling `run(param)`. Receives the same arguments as `promiseFn`. The `deferFn` is commonly used to send data to the server following a user action, such as submitting a form. You can use this in conjunction with `promiseFn` to fill the form with existing data, then updating it on submit with `deferFn`.
 
 > Be aware that when using both `promiseFn` and `deferFn`, the shape of their fulfilled value should match, because they both update the same `data`.
 
@@ -132,3 +133,10 @@ Enables the use of `deferFn` if `true`, or enables the use of `promiseFn` if `fa
 > `boolean`
 
 Enables or disables JSON parsing of the response body. By default this is automatically enabled if the `Accept` header is set to `"application/json"`.
+
+
+## `context`
+
+> `C | undefined`
+
+The argument which is passed as the first argument to the `promiseFn` and the `deferFn`.

docs/getting-started/upgrading.md

@@ -1,5 +1,206 @@
 # Upgrading
 
+## Upgrade to v11
+
+### promiseFn and deferFn unification
+
+The `promiseFn` and the `deferFn` have been unified. They now share the following signature:
+
+```ts
+export type AsyncFn<T, C> = (
+  context: C | undefined,
+  props: AsyncProps<T, C>,
+  controller: AbortController
+) => Promise<T>
+```
+
+Before the `deferFn` and `promiseFn` had this signature:
+
+```ts
+export type PromiseFn<T> = (props: AsyncProps<T>, controller: AbortController) => Promise<T>
+
+export type DeferFn<T> = (
+  args: any[],
+  props: AsyncProps<T>,
+  controller: AbortController
+) => Promise<T>
+```
+
+The difference is the idea of having a `context`, the context will contain all parameters
+to `AsyncProps` which are not native to the `AsyncProps`. Before you could pass any parameter
+to `AsyncProps` and it would pass them to the `deferFn` and `promiseFn`, now you need to use
+the `context` instead.
+
+For example before you could write:
+
+```jsx
+useAsync({ promiseFn: loadPlayer, playerId: 1 })
+```
+
+Now you must write:
+
+```jsx
+useAsync({ promiseFn: loadPlayer, context: { playerId: 1 }})
+```
+
+In the above example the context would be `{playerId: 1}`.
+
+This means that `promiseFn` now expects three parameters instead of two.
+
+So before in `< 10.0.0` you would do this:
+
+```jsx
+import { useAsync } from "react-async"
+
+// Here loadPlayer has only two arguments
+const loadPlayer = async (options, controller) => {
+  const res = await fetch(`/api/players/${options.playerId}`, { signal: controller.signal })
+  if (!res.ok) throw new Error(res.statusText)
+  return res.json()
+}
+
+// With hooks
+const MyComponent = () => {
+  const state = useAsync({ promiseFn: loadPlayer, playerId: 1 })
+}
+
+// With the Async component
+<Async promiseFn={loadPlayer} playerId={1} />
+```
+
+In `11.0.0` you need to account for the three parameters:
+
+```jsx
+import { useAsync } from "react-async"
+
+// Now it has three arguments
+const loadPlayer = async (context, options, controller) => {
+  const res = await fetch(`/api/players/${context.playerId}`, { signal: controller.signal })
+  if (!res.ok) throw new Error(res.statusText)
+  return res.json()
+}
+
+// With hooks
+const MyComponent = () => {
+  const state = useAsync({ promiseFn: loadPlayer, context: { playerId: 1 } })
+}
+
+// With the Async component
+<Async promiseFn={loadPlayer} context={{ playerId: 1 }} />
+```
+
+For the `deferFn` this means no longer expecting an array of arguments but instead a singular argument.
+The `run` now accepts only one argument which is a singular value. All other arguments to `run` but
+the first will be ignored.
+
+So before in `< 10.0.0` you would do this:
+
+```jsx
+import Async from "react-async"
+
+const getAttendance = () =>
+  fetch("/attendance").then(
+    () => true,
+    () => false
+  )
+const updateAttendance = ([attend, userId]) =>
+  fetch(`/attendance/${userId}`, { method: attend ? "POST" : "DELETE" }).then(
+    () => attend,
+    () => !attend
+  )
+
+const userId = 42
+
+const AttendanceToggle = () => (
+  <Async promiseFn={getAttendance} deferFn={updateAttendance}>
+    {({ isPending, data: isAttending, run, setData }) => (
+      <Toggle
+        on={isAttending}
+        onClick={() => {
+          run(!isAttending, userId)
+        }}
+        disabled={isPending}
+      />
+    )}
+  </Async>
+)
+```
+
+In `11.0.0` you need to account for for the parameters not being an array:
+
+```jsx
+import Async from "react-async"
+
+const getAttendance = () =>
+  fetch("/attendance").then(
+    () => true,
+    () => false
+  )
+const updateAttendance = ({ attend, userId }) =>
+  fetch(`/attendance/${userId}`, { method: attend ? "POST" : "DELETE" }).then(
+    () => attend,
+    () => !attend
+  )
+
+const userId = 42
+
+const AttendanceToggle = () => (
+  <Async promiseFn={getAttendance} deferFn={updateAttendance}>
+    {({ isPending, data: isAttending, run, setData }) => (
+      <Toggle
+        on={isAttending}
+        onClick={() => {
+          run({ attend: isAttending, userId })
+        }}
+        disabled={isPending}
+      />
+    )}
+  </Async>
+)
+```
+
+### useAsync only accepts one prop
+
+Before in `10.0.0` you could call useAsync with multiple parameters,
+the first argument would then be the `promiseFn` like this:
+
+```tsx
+const state = useAsync(loadPlayer, { context: { playerId: 1 } })
+```
+
+In `11.0.0` there is only one parameter. So the overload no longer works and you need to write this instead:
+
+```tsx
+const state = useAsync({ promiseFn: loadPlayer, context: { playerId: 1 } })
+```
+
+### WatchFn
+
+Another thing you need to be careful about is the `watchFn` you can no longer count on the fact that 
+unknown parameters are put into the `AsyncProps`. Before `< 10.0.0` you would write:
+
+```ts
+useAsync({ 
+  promiseFn, 
+  count: 0, 
+  watchFn: (props, prevProps) => props.count !== prevProps.count 
+});
+```
+
+In `11.0.0` you need to use the `context` instead:
+
+```ts
+useAsync({ 
+  promiseFn, 
+  context: { count: 0 }, 
+  watchFn: (props, prevProps) => props.context.count !== prevProps.context.count 
+});
+```
+
+## Upgrade to v10
+
+This is a major release due to the migration to TypeScript. While technically it shouldn't change anything, it might be a breaking change in certain situations. Theres also a bugfix for watchFn and a fix for legacy browsers.
+
 ## Upgrade to v9
 
 The rejection value for failed requests with `useFetch` was changed. Previously it was the Response object. Now it's an

docs/getting-started/usage.md

@@ -10,14 +10,14 @@ The `useAsync` hook \(available [from React v16.8.0](https://reactjs.org/hooks)\
 import { useAsync } from "react-async"
 
 // You can use async/await or any function that returns a Promise
-const loadPlayer = async ({ playerId }, { signal }) => {
+const loadPlayer = async ({ playerId }, options, { signal }) => {
   const res = await fetch(`/api/players/${playerId}`, { signal })
   if (!res.ok) throw new Error(res.statusText)
   return res.json()
 }
 
 const MyComponent = () => {
-  const { data, error, isPending } = useAsync({ promiseFn: loadPlayer, playerId: 1 })
+  const { data, error, isPending } = useAsync({ promiseFn: loadPlayer, context: { playerId: 1 } })
   if (isPending) return "Loading..."
   if (error) return `Something went wrong: ${error.message}`
   if (data)
@@ -37,7 +37,7 @@ Or using the shorthand version:
 
 ```jsx
 const MyComponent = () => {
-  const { data, error, isPending } = useAsync(loadPlayer, options)
+  const { data, error, isPending } = useAsync({ promiseFn: loadPlayer, context: { playerId: 1 } })
   // ...
 }
 ```
@@ -85,14 +85,14 @@ The classic interface to React Async. Simply use `<Async>` directly in your JSX
 import Async from "react-async"
 
 // Your promiseFn receives all props from Async and an AbortController instance
-const loadPlayer = async ({ playerId }, { signal }) => {
+const loadPlayer = async ({ playerId }, options, { signal }) => {
   const res = await fetch(`/api/players/${playerId}`, { signal })
   if (!res.ok) throw new Error(res.statusText)
   return res.json()
 }
 
 const MyComponent = () => (
-  <Async promiseFn={loadPlayer} playerId={1}>
+  <Async promiseFn={loadPlayer} context={{ playerId: 1}}>
     {({ data, error, isPending }) => {
       if (isPending) return "Loading..."
       if (error) return `Something went wrong: ${error.message}`
@@ -118,7 +118,7 @@ You can also create your own component instances, allowing you to preconfigure t
 ```jsx
 import { createInstance } from "react-async"
 
-const loadPlayer = async ({ playerId }, { signal }) => {
+const loadPlayer = async ({ playerId }, options, { signal }) => {
   const res = await fetch(`/api/players/${playerId}`, { signal })
   if (!res.ok) throw new Error(res.statusText)
   return res.json()
@@ -128,7 +128,7 @@ const loadPlayer = async ({ playerId }, { signal }) => {
 const AsyncPlayer = createInstance({ promiseFn: loadPlayer }, "AsyncPlayer")
 
 const MyComponent = () => (
-  <AsyncPlayer playerId={1}>
+  <AsyncPlayer context={{playerId: 1}}>
     <AsyncPlayer.Fulfilled>{player => `Hello ${player.name}`}</AsyncPlayer.Fulfilled>
   </AsyncPlayer>
 )
@@ -141,12 +141,12 @@ Several [helper components](usage.md#helper-components) are available to improve
 ```jsx
 import { useAsync, IfPending, IfFulfilled, IfRejected } from "react-async"
 
-const loadPlayer = async ({ playerId }, { signal }) => {
+const loadPlayer = async ({ playerId }, options, { signal }) => {
   // ...
 }
 
 const MyComponent = () => {
-  const state = useAsync({ promiseFn: loadPlayer, playerId: 1 })
+  const state = useAsync({ promiseFn: loadPlayer, context: { playerId: 1 } })
   return (
     <>
       <IfPending state={state}>Loading...</IfPending>
@@ -171,14 +171,14 @@ Each of the helper components are also available as static properties of `<Async
 ```jsx
 import Async from "react-async"
 
-const loadPlayer = async ({ playerId }, { signal }) => {
+const loadPlayer = async ({ playerId }, options, { signal }) => {
   const res = await fetch(`/api/players/${playerId}`, { signal })
   if (!res.ok) throw new Error(res.statusText)
   return res.json()
 }
 
 const MyComponent = () => (
-  <Async promiseFn={loadPlayer} playerId={1}>
+  <Async promiseFn={loadPlayer} context={{playerId: 1 }}>
     <Async.Pending>Loading...</Async.Pending>
     <Async.Fulfilled>
       {data => (

docs/guide/async-actions.md

@@ -12,7 +12,7 @@ automatically invoked by React Async when rendering the component. Instead it wi
 import React, { useState } from "react"
 import { useAsync } from "react-async"
 
-const subscribe = ([email], props, { signal }) =>
+const subscribe = ({email}, options, { signal }) =>
   fetch("/newsletter", { method: "POST", body: JSON.stringify({ email }), signal })
 
 const NewsletterForm = () => {
@@ -21,7 +21,7 @@ const NewsletterForm = () => {
 
   const handleSubmit = event => {
     event.preventDefault()
-    run(email)
+    run({email})
   }
 
   return (
@@ -36,11 +36,11 @@ const NewsletterForm = () => {
 }
 ```
 
-As you can see, the `deferFn` is invoked with 3 arguments: `args`, `props` and the AbortController. `args` is an array
+As you can see, the `deferFn` is invoked with 3 arguments: `context`, `props` and the AbortController. `context` is an object
 representing the arguments that were passed to `run`. In this case we passed the `email`, so we can extract that from
-the `args` array at the first index using [array destructuring] and pass it along to our `fetch` request.
+the `context` prop using [object destructuring] and pass it along to our `fetch` request.
 
-[array destructuring]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment#Array_destructuring
+[object destructuring]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Destructuring_assignment#Object_destructuring
 
 ## Sending data with `useFetch`