From 397b9d423ee6bd699c3c488c237decc67e10c4a6 Mon Sep 17 00:00:00 2001
From: Jordan Frankfurt <jordanwfrankfurt@gmail.com>
Date: Thu, 22 Sep 2022 13:06:31 -0500
Subject: [PATCH] feat(explore): rewrite top tokens hook (#4697)

rewrite top tokens hook
---
 .../Tokens/TokenTable/TokenTable.tsx          | 31 ++-----
 src/graphql/data/Token.ts                     |  1 -
 src/graphql/data/TopTokens.ts                 | 88 ++++++++++---------
 3 files changed, 54 insertions(+), 66 deletions(-)

diff --git a/src/components/Tokens/TokenTable/TokenTable.tsx b/src/components/Tokens/TokenTable/TokenTable.tsx
index 58519c733c..1ae0dd052b 100644
--- a/src/components/Tokens/TokenTable/TokenTable.tsx
+++ b/src/components/Tokens/TokenTable/TokenTable.tsx
@@ -116,28 +116,15 @@ export default function TokenTable() {
           <GridContainer>
             <HeaderRow />
             <TokenDataContainer>
-              {tokens.map((token, index) => {
-                if (tokens.length === index + 1) {
-                  return (
-                    <LoadedRow
-                      key={token?.name}
-                      tokenListIndex={index}
-                      tokenListLength={tokens?.length ?? 0}
-                      token={token}
-                      ref={lastTokenRef}
-                    />
-                  )
-                } else {
-                  return (
-                    <LoadedRow
-                      key={token?.name}
-                      tokenListIndex={index}
-                      tokenListLength={tokens?.length ?? 0}
-                      token={token}
-                    />
-                  )
-                }
-              })}
+              {tokens.map((token, index) => (
+                <LoadedRow
+                  key={token?.name}
+                  tokenListIndex={index}
+                  tokenListLength={tokens?.length ?? 0}
+                  token={token}
+                  ref={tokens.length === index + 1 ? lastTokenRef : undefined}
+                />
+              ))}
               {loading && LoadingMoreRows}
             </TokenDataContainer>
           </GridContainer>
diff --git a/src/graphql/data/Token.ts b/src/graphql/data/Token.ts
index f6ac3ec033..d4448895f5 100644
--- a/src/graphql/data/Token.ts
+++ b/src/graphql/data/Token.ts
@@ -113,7 +113,6 @@ const tokenQuery = graphql`
 `
 
 export function useTokenQuery(address: string, chain: Chain, timePeriod: TimePeriod) {
-  //const cachedTopToken = cachedTopTokens[address]
   const data = useLazyLoadQuery<TokenQuery>(tokenQuery, {
     contract: { address, chain },
     duration: toHistoryDuration(timePeriod),
diff --git a/src/graphql/data/TopTokens.ts b/src/graphql/data/TopTokens.ts
index dbf4ee1536..bdda7989ce 100644
--- a/src/graphql/data/TopTokens.ts
+++ b/src/graphql/data/TopTokens.ts
@@ -18,9 +18,8 @@ import { toHistoryDuration, useCurrentChainName } from './util'
 export function usePrefetchTopTokens() {
   const duration = toHistoryDuration(useAtomValue(filterTimeAtom))
   const chain = useCurrentChainName()
-
-  const top100 = useLazyLoadQuery<TopTokens100Query>(topTokens100Query, { duration, chain })
-  return top100
+  const args = useMemo(() => ({ chain, duration }), [chain, duration])
+  return useLazyLoadQuery<TopTokens100Query>(topTokens100Query, args)
 }
 
 const topTokens100Query = graphql`
@@ -131,59 +130,62 @@ function toContractInput(token: PrefetchedTopToken) {
 }
 
 export type TopToken = NonNullable<TopTokens_TokensQuery['response']['tokens']>[number]
-export function useTopTokens(prefetchedData: TopTokens100Query['response']) {
+interface UseTopTokensReturnValue {
+  loading: boolean
+  tokens: TopToken[]
+  loadMoreTokens: () => void
+}
+export function useTopTokens(prefetchedData: TopTokens100Query['response']): UseTopTokensReturnValue {
   const duration = toHistoryDuration(useAtomValue(filterTimeAtom))
   const environment = useRelayEnvironment()
-  const [tokens, setTokens] = useState<TopToken[]>()
+  const [tokens, setTokens] = useState<TopToken[]>([])
 
-  const [page, setPage] = useState(1)
-  const prefetchedSelectedTokens = useFilteredTokens(useSortedTokens(prefetchedData.topTokens))
+  const [page, setPage] = useState(0)
   const [loading, setLoading] = useState(true)
 
+  const appendTokens = useCallback(
+    (newTokens: TopToken[]) => {
+      setTokens(
+        Object.values(
+          tokens
+            .concat(newTokens)
+            .reduce((acc, token) => (token?.address ? { ...acc, [token.address]: token } : acc), {})
+        )
+      )
+    },
+    [tokens]
+  )
+  const loadMoreTokens = useCallback(() => setPage(page + 1), [page])
+
   // 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 loadTokens = useCallback(
-    (contracts: ContractInput[], onSuccess: (data: TopTokens_TokensQuery['response'] | undefined) => void) => {
-      fetchQuery<TopTokens_TokensQuery>(
-        environment,
-        tokensQuery,
-        { contracts, duration },
-        { fetchPolicy: 'store-or-network' }
-      )
-        .toPromise()
-        .then(onSuccess)
-    },
-    [duration, environment]
+  const prefetchedSelectedTokens = useFilteredTokens(useSortedTokens(prefetchedData.topTokens))
+  const contracts: ContractInput[] = useMemo(
+    () => prefetchedSelectedTokens.slice(page * PAGE_SIZE, (page + 1) * PAGE_SIZE).map(toContractInput),
+    [page, prefetchedSelectedTokens]
   )
 
-  const loadMoreTokens = useCallback(() => {
-    setLoading(true)
-    const contracts = prefetchedSelectedTokens.slice(page * PAGE_SIZE, (page + 1) * PAGE_SIZE).map(toContractInput)
-    loadTokens(contracts, (data) => {
-      if (data?.tokens) {
-        setTokens([...(tokens ?? []), ...data.tokens])
-        setLoading(false)
-        setPage(page + 1)
-      }
-    })
-  }, [loadTokens, page, prefetchedSelectedTokens, tokens])
-
-  // Reset count when filters are changed
   useEffect(() => {
-    setLoading(true)
-    setTokens([])
-    const contracts = prefetchedSelectedTokens.slice(0, PAGE_SIZE).map(toContractInput)
-    loadTokens(contracts, (data) => {
-      if (data?.tokens) {
-        // @ts-ignore prevent typescript from complaining about readonly data
-        setTokens(data.tokens)
+    const subscription = fetchQuery<TopTokens_TokensQuery>(
+      environment,
+      tokensQuery,
+      { contracts, duration },
+      { fetchPolicy: 'store-or-network' }
+    ).subscribe({
+      start() {
+        setLoading(true)
+      },
+      complete() {
         setLoading(false)
-        setPage(1)
-      }
+      },
+      next(data) {
+        appendTokens(data.tokens as TopToken[])
+      },
     })
-  }, [loadTokens, prefetchedSelectedTokens])
+    return subscription.unsubscribe
+  }, [appendTokens, contracts, duration, environment])
 
-  return { loading, tokens, loadMoreTokens }
+  return { loading, tokens: useFilteredTokens(useSortedTokens(tokens)) as TopToken[], loadMoreTokens }
 }
 
 export const tokensQuery = graphql`