feat: add useContext helper function

`useContext` returns the Nuxt context without the need for a callback

BREAKING CHANGE: `withContext` is now deprecated
Closes #29

Author: danielroe

README.md

@@ -117,18 +117,17 @@ const val2 = ssrRef(myExpensiveSetterFunction)
 
 **Note**: Under the hood, `ssrRef` requires a key to ensure that the ref values match between client and server. If you have added `nuxt-composition-api` to your `buildModules`, this will be done automagically by an injected Babel plugin. If you need to do things differently, you can specify a key manually or add `nuxt-composition-api/babel` to your Babel plugins.
 
-### withContext
+### useContext
 
-You can access the Nuxt context more easily using `withContext`, which will immediately call the callback and pass it the Nuxt context.
+You can access the Nuxt context more easily using `useContext`, which will return the Nuxt context.
 
 ```ts
-import { defineComponent, ref, withContext } from 'nuxt-composition-api'
+import { defineComponent, ref, useContext } from 'nuxt-composition-api'
 
 export default defineComponent({
   setup() {
-    withContext(({ store }) => {
-      store.dispatch('myAction')
-    })
+    const { store } = useContext()
+    store.dispatch('myAction')
   },
 })
 ```

src/context.ts

@@ -5,9 +5,20 @@ interface ContextCallback {
   (context: Context): void
 }
 
+/**
+ * @deprecated
+ * Recommend using `useContext` instead
+ */
 export const withContext = (callback: ContextCallback) => {
   const vm = getCurrentInstance()
   if (!vm) throw new Error('This must be called within a setup function.')
 
   callback(vm.$nuxt.context)
 }
+
+export const useContext = () => {
+  const vm = getCurrentInstance()
+  if (!vm) throw new Error('This must be called within a setup function.')
+
+  return vm.$nuxt.context
+}