Merge pull request #64 from PrefectHQ/subscriptions-with-dependencies

Feature: useSubscriptionWithDependencies

Author: pleek91

src/useSubscription/index.ts

@@ -1,4 +1,5 @@
 export * from './utilities'
 export * from './models'
 export * from './types'
-export * from './useSubscription'
+export * from './useSubscription'
+export * from './useSubscriptionWithDependencies'

src/useSubscription/useSubscription.ts

@@ -1,4 +1,4 @@
-import { getCurrentInstance, onUnmounted, reactive, watch } from 'vue'
+import { getCurrentInstance, onUnmounted, reactive, unref, watch } from 'vue'
 import Manager from './models/manager'
 import { Action, ActionArguments } from './types/action'
 import { SubscribeArguments, UseSubscription } from './types/subscription'
@@ -18,7 +18,8 @@ export function useSubscription<T extends Action>(...[action, args, options = {}
 
   if (watchable !== null) {
     unwatch = watch(watchable, () => {
-      if (!subscriptionResponse.isSubscribed()) {
+      // checking if args are null to support useSubscriptionWithDependencies
+      if (!subscriptionResponse.isSubscribed() || unref(argsWithDefault) === null) {
         unwatch!()
         return
       }

src/useSubscription/useSubscriptionWithDependencies.ts

@@ -0,0 +1,33 @@
+import { Ref, watchEffect } from 'vue'
+import { Action, SubscriptionOptions, UseSubscription, ActionArguments } from './types'
+import { useSubscription } from './useSubscription'
+
+const voidAction = (): undefined => undefined
+
+type UseSubscriptionWithDependencies<T extends Action> = [
+  action: T,
+  args: Ref<Parameters<T> | null>,
+  options?: SubscriptionOptions
+]
+
+export function useSubscriptionWithDependencies<T extends Action>(...[action, args, options = {}]: UseSubscriptionWithDependencies<T>): UseSubscription<T | typeof voidAction> {
+  const subscription = useSubscription(voidAction)
+
+  watchEffect(() => {
+    if (args.value === null) {
+      if (subscription.isSubscribed()) {
+        subscription.unsubscribe()
+      }
+
+      Object.assign(subscription, useSubscription(voidAction))
+
+      return
+    }
+
+    const newSubscription = useSubscription(action, args as ActionArguments<T>, options)
+
+    Object.assign(subscription, newSubscription)
+  })
+
+  return subscription
+}