fix: glitchy lazy loading (big jump / unnecessary scroll) (#4776)

* fix glitchy loading

* fix initial no tokens state

src/components/Tokens/TokenTable/TokenTable.tsx

@@ -72,8 +72,7 @@ export default function TokenTable() {
 
   // TODO: consider moving prefetched call into app.tsx and passing it here, use a preloaded call & updated on interval every 60s
   const chainName = validateUrlChainParam(useParams<{ chainName?: string }>().chainName)
-  const { loading, tokens, tokensWithoutPriceHistoryCount, hasMore, loadMoreTokens, maxFetchable } =
-    useTopTokens(chainName)
+  const { error, loading, tokens, hasMore, loadMoreTokens, maxFetchable } = useTopTokens(chainName)
   const showMoreLoadingRows = Boolean(loading && hasMore)
 
   const observer = useRef<IntersectionObserver>()
@@ -93,9 +92,9 @@ export default function TokenTable() {
 
   /* loading and error state */
   if (loading && (!tokens || tokens?.length === 0)) {
-    return <LoadingTokenTable rowCount={Math.min(tokensWithoutPriceHistoryCount, PAGE_SIZE)} />
+    return <LoadingTokenTable rowCount={PAGE_SIZE} />
   } else {
-    if (!tokens) {
+    if (error || !tokens) {
       return (
         <NoTokensState
           message={

src/graphql/data/TopTokens.ts

@@ -8,8 +8,8 @@ import {
   sortMethodAtom,
 } from 'components/Tokens/state'
 import { useAtomValue } from 'jotai/utils'
-import { useCallback, useLayoutEffect, useMemo, useState } from 'react'
-import { fetchQuery, useLazyLoadQuery, useRelayEnvironment } from 'react-relay'
+import { useCallback, useEffect, useLayoutEffect, useMemo, useState } from 'react'
+import { fetchQuery, useRelayEnvironment } from 'react-relay'
 
 import {
   Chain,
@@ -20,10 +20,6 @@ import {
 import type { TopTokens100Query } from './__generated__/TopTokens100Query.graphql'
 import { toHistoryDuration } from './util'
 
-export function usePrefetchTopTokens(duration: HistoryDuration, chain: Chain) {
-  return useLazyLoadQuery<TopTokens100Query>(topTokens100Query, { duration, chain })
-}
-
 const topTokens100Query = graphql`
   query TopTokens100Query($duration: HistoryDuration!, $chain: Chain!) {
     topTokens(pageSize: 100, page: 1, chain: $chain) {
@@ -166,29 +162,48 @@ const checkIfAllTokensCached = (duration: HistoryDuration, tokens: PrefetchedTop
 
 export type TopToken = NonNullable<TopTokens_TokensQuery['response']['tokens']>[number]
 interface UseTopTokensReturnValue {
+  error: Error | undefined
   loading: boolean
   tokens: TopToken[] | undefined
-  tokensWithoutPriceHistoryCount: number
   hasMore: boolean
   loadMoreTokens: () => void
   maxFetchable: number
 }
 export function useTopTokens(chain: Chain): UseTopTokensReturnValue {
   const duration = toHistoryDuration(useAtomValue(filterTimeAtom))
-  const [loading, setLoading] = useState(true)
+  const [loadingTokensWithoutPriceHistory, setLoadingTokensWithoutPriceHistory] = useState(true)
+  const [loadingTokensWithPriceHistory, setLoadingTokensWithPriceHistory] = useState(true)
   const [tokens, setTokens] = useState<TopToken[]>()
   const [page, setPage] = useState(0)
-  const prefetchedData = usePrefetchTopTokens(duration, chain)
-  const prefetchedSelectedTokensWithoutPriceHistory = useFilteredTokens(useSortedTokens(prefetchedData.topTokens))
+  const [error, setError] = useState<Error | undefined>()
+  const [prefetchedData, setPrefetchedData] = useState<PrefetchedTopToken[]>([])
+  const prefetchedSelectedTokensWithoutPriceHistory = useFilteredTokens(useSortedTokens(prefetchedData))
   const maxFetchable = useMemo(
     () => prefetchedSelectedTokensWithoutPriceHistory.length,
     [prefetchedSelectedTokensWithoutPriceHistory]
   )
 
   const hasMore = !tokens || tokens.length < prefetchedSelectedTokensWithoutPriceHistory.length
-
   const environment = useRelayEnvironment()
 
+  const loadTokensWithoutPriceHistory = useCallback(
+    ({ duration, chain }: { duration: HistoryDuration; chain: Chain }) => {
+      fetchQuery<TopTokens100Query>(
+        environment,
+        topTokens100Query,
+        { duration, chain },
+        { fetchPolicy: 'store-or-network' }
+      ).subscribe({
+        next: (data) => {
+          if (data?.topTokens) setPrefetchedData([...data?.topTokens])
+        },
+        error: setError,
+        complete: () => setLoadingTokensWithoutPriceHistory(false),
+      })
+    },
+    [environment]
+  )
+
   // TopTokens should ideally be fetched with usePaginationFragment. The backend does not current support graphql cursors;
   // in the meantime, fetchQuery is used, as other relay hooks do not allow the refreshing and lazy loading we need
   const loadTokensWithPriceHistory = useCallback(
@@ -208,25 +223,27 @@ export function useTopTokens(chain: Chain): UseTopTokensReturnValue {
         tokensQuery,
         { contracts, duration },
         { fetchPolicy: 'store-or-network' }
-      )
-        .toPromise()
-        .then((data) => {
+      ).subscribe({
+        next: (data) => {
           if (data?.tokens) {
             const priceHistoryCacheForCurrentDuration = tokensWithPriceHistoryCache[duration]
             data.tokens.map((token) =>
               !!token ? (priceHistoryCacheForCurrentDuration[`${token.chain}${token.address}`] = token) : null
             )
             appendingTokens ? setTokens([...(tokens ?? []), ...data.tokens]) : setTokens([...data.tokens])
-            setLoading(false)
+            setLoadingTokensWithPriceHistory(false)
             setPage(page + 1)
           }
+        },
+        error: setError,
+        complete: () => setLoadingTokensWithPriceHistory(false),
       })
     },
     [duration, environment]
   )
 
   const loadMoreTokens = useCallback(() => {
-    setLoading(true)
+    setLoadingTokensWithPriceHistory(true)
     const contracts = prefetchedSelectedTokensWithoutPriceHistory
       .slice(page * PAGE_SIZE, (page + 1) * PAGE_SIZE)
       .map(toContractInput)
@@ -241,21 +258,27 @@ export function useTopTokens(chain: Chain): UseTopTokensReturnValue {
     )
     if (everyTokenInCache) {
       setTokens(cachedTokens)
-      setLoading(false)
-      return
+      setLoadingTokensWithPriceHistory(false)
     } else {
-      setLoading(true)
+      setLoadingTokensWithPriceHistory(true)
       setTokens([])
       const contracts = prefetchedSelectedTokensWithoutPriceHistory.slice(0, PAGE_SIZE).map(toContractInput)
       loadTokensWithPriceHistory({ contracts, appendingTokens: false, page: 0 })
     }
   }, [loadTokensWithPriceHistory, prefetchedSelectedTokensWithoutPriceHistory, duration])
 
+  // Trigger fetching top 100 tokens without price history on first load, and on
+  // each change of chain or duration.
+  useEffect(() => {
+    setLoadingTokensWithoutPriceHistory(true)
+    loadTokensWithoutPriceHistory({ duration, chain })
+  }, [chain, duration, loadTokensWithoutPriceHistory])
+
   return {
-    loading,
+    error,
+    loading: loadingTokensWithPriceHistory || loadingTokensWithoutPriceHistory,
     tokens,
     hasMore,
-    tokensWithoutPriceHistoryCount: prefetchedSelectedTokensWithoutPriceHistory.length,
     loadMoreTokens,
     maxFetchable,
   }