replace deriveAsync and deriveAsyncIfDefined with runed resource (#1695)

* replace deriveAsync and deriveAsyncIfDefined with runed resource

* Fix type error

Runed resource requires an async fetcher function, so even when we can
resolve without async we need to return a resolved Promise.

---------

Co-authored-by: Robin Munn <rmunn@pobox.com>

Author: hahn-kev

frontend/src/lib/forms/UserTypeahead.svelte

@@ -2,8 +2,7 @@
   import { FormField, PlainInput, randomFormId } from '$lib/forms';
   import { _userTypeaheadSearch, _usersTypeaheadSearch, type SingleUserTypeaheadResult, type SingleUserICanSeeTypeaheadResult } from '$lib/gql/typeahead-queries';
   import { overlay } from '$lib/overlay';
-  import { deriveAsync } from '$lib/util/time';
-  import { writable } from 'svelte/store';
+  import {resource} from 'runed';
 
   type UserTypeaheadResult = SingleUserTypeaheadResult | SingleUserICanSeeTypeaheadResult;
   let inputComponent: PlainInput | undefined = $state();
@@ -40,15 +39,14 @@
 
   // making this explicit allows us to only react to input events,
   // rather than programmatic changes like selecting a user
-  let trigger = writable('');
-  const _typeaheadResults = deriveAsync(trigger, (value) => typeaheadSearch(value), [], debounceMs);
+  let trigger = $state('');
+  const _typeaheadResults = resource(() => trigger, (value) => typeaheadSearch(value), {initialValue: [], debounce: debounceMs});
 
-  // TODO: Turn this into state instead of a store at some point
-  let selectedUser = writable<UserTypeaheadResult | null>(null);
+  let selectedUser = $state<UserTypeaheadResult | null>(null);
 
   function selectUser(user: UserTypeaheadResult): void {
-    $selectedUser = user;
-    onSelectedUserChange?.($selectedUser);
+    selectedUser = user;
+    onSelectedUserChange?.(selectedUser);
     selectedValue = getInputValue(user);
     value = selectedValue;
   }
@@ -99,14 +97,14 @@
       typeaheadResults = []; // prevent old results showing when opening next time
     }
   }
-  let typeaheadResults = $derived($_typeaheadResults);
+  let typeaheadResults = $derived(_typeaheadResults.current);
   let filteredResults = $derived(typeaheadResults.filter((user) => !exclude.includes(user.id)));
   // TODO: Can this be simplified by making the "value !== selectedValue" part into a $derived?
   // Then we'd be able to just do `$effect(() => { if (changedSelection) dispatch(...)})`
   // And, of course, change the dispatch into calling a prop function
   $effect(() => {
-    if ($selectedUser && value !== selectedValue) {
-      $selectedUser = null;
+    if (selectedUser && value !== selectedValue) {
+      selectedUser = null;
       selectedValue = undefined;
       onSelectedUserChange?.(null);
     }
@@ -131,7 +129,7 @@
       autocomplete="off"
       {autofocus}
       {keydownHandler}
-      onInput={(value) => trigger.set(value ?? '')}
+      onInput={(value) => trigger = value ?? ''}
     />
     <div class="overlay-content">
       <ul class="menu p-0">

frontend/src/lib/util/time.test.ts

@@ -1,5 +1,3 @@
-import { writable, type Readable, derived } from 'svelte/store';
-
 export const enum Duration {
   Persistent = 0,
   Default = 5000,
@@ -12,96 +10,3 @@ export async function delay<T>(ms: Duration | number = Duration.Default): Promis
 }
 
 export const DEFAULT_DEBOUNCE_TIME = 400;
-
-// eslint-disable-next-line @typescript-eslint/no-explicit-any
-interface Debouncer<P extends any[]> {
-  debounce: (...args: P) => void;
-  debouncing: Readable<boolean>;
-  clear: () => void;
-}
-
-function pickDebounceTime(debounce: number | boolean): number {
-  return typeof debounce === 'number' ? debounce : DEFAULT_DEBOUNCE_TIME;
-}
-
-// eslint-disable-next-line @typescript-eslint/no-explicit-any
-export function makeDebouncer<P extends any[]>(fn: Debouncer<P>['debounce'], debounce: number | boolean = DEFAULT_DEBOUNCE_TIME): Debouncer<P> {
-  const debouncing = writable(false);
-
-  if (!debounce) {
-    return { debounce: fn, debouncing, clear: () => { } };
-  } else {
-    const debounceTime = pickDebounceTime(debounce);
-    let timeout: ReturnType<typeof setTimeout>;
-    return {
-      debounce: (...args: P) => {
-        debouncing.set(true);
-        clearTimeout(timeout);
-        timeout = setTimeout(() => {
-          try {
-            fn(...args);
-          } finally {
-            debouncing.set(false);
-          }
-        }, debounceTime);
-      },
-      debouncing,
-      clear: () => {
-        clearTimeout(timeout);
-        debouncing.set(false);
-      },
-    };
-  }
-}
-
-/**
- * @param fn A function that maps the store value to an async result
- * @returns A store that contains the result of the async function, optionally debounced
- */
-export function deriveAsync<T, D>(
-  store: Readable<T>,
-  fn: (value: T) => Promise<D>,
-  initialValue?: D,
-  debounce: number | boolean = false): Readable<D> {
-
-  const debounceTime = pickDebounceTime(debounce);
-  let timeout: ReturnType<typeof setTimeout> | undefined;
-
-  return derived(store, (value, set) => {
-    clearTimeout(timeout);
-    timeout = setTimeout(() => {
-      const myTimeout = timeout;
-      void fn(value).then((result) => {
-        if (myTimeout !== timeout) return; // discard outdated results
-        set(result);
-      });
-    }, debounceTime);
-  }, initialValue);
-}
-
-/**
- * @param fn A function that maps the store value to an async result, filtering out undefined values
- * @returns A store that contains the result of the async function
- */
-export function deriveAsyncIfDefined<T, D>(
-  store: Readable<T | undefined>,
-  fn: (value: T) => Promise<D>,
-  initialValue?: D,
-  debounce: number | boolean = false): Readable<D> {
-
-  const debounceTime = pickDebounceTime(debounce);
-  let timeout: ReturnType<typeof setTimeout> | undefined;
-
-  return derived(store, (value, set) => {
-    if (value) {
-      clearTimeout(timeout);
-      timeout = setTimeout(() => {
-        const myTimeout = timeout;
-          void fn(value).then((result) => {
-            if (myTimeout !== timeout) return; // discard outdated results
-            set(result);
-          });
-      }, debounceTime);
-    }
-  }, initialValue);
-}