fix: fetch decimals from token query (#5016)

* feat: add decimals, wrapper to token query

* fix: construct token in details page

src/graphql/data/Token.ts

@@ -1,11 +1,13 @@
 import graphql from 'babel-plugin-relay/macro'
+import { DEFAULT_ERC20_DECIMALS } from 'constants/tokens'
 import { useMemo, useState } from 'react'
 import { fetchQuery, useLazyLoadQuery } from 'react-relay'
+import { WrappedTokenInfo } from 'state/lists/wrappedTokenInfo'
 
 import { Chain, TokenPriceQuery } from './__generated__/TokenPriceQuery.graphql'
 import { ContractInput, HistoryDuration, TokenQuery, TokenQuery$data } from './__generated__/TokenQuery.graphql'
 import environment from './RelayEnvironment'
-import { TimePeriod, toHistoryDuration } from './util'
+import { CHAIN_NAME_TO_CHAIN_ID, TimePeriod, toHistoryDuration } from './util'
 
 /*
 The difference between Token and TokenProject:
@@ -19,6 +21,7 @@ const tokenQuery = graphql`
   query TokenQuery($contract: ContractInput!, $duration: HistoryDuration!) {
     tokens(contracts: [$contract]) {
       id @required(action: LOG)
+      decimals
       name
       chain @required(action: LOG)
       address @required(action: LOG)
@@ -61,6 +64,42 @@ const tokenQuery = graphql`
   }
 `
 
+const tokenPriceQuery = graphql`
+  query TokenPriceQuery(
+    $contract: ContractInput!
+    $skip1H: Boolean!
+    $skip1D: Boolean!
+    $skip1W: Boolean!
+    $skip1M: Boolean!
+    $skip1Y: Boolean!
+  ) {
+    tokens(contracts: [$contract]) {
+      market(currency: USD) {
+        priceHistory1H: priceHistory(duration: HOUR) @skip(if: $skip1H) {
+          timestamp
+          value
+        }
+        priceHistory1D: priceHistory(duration: DAY) @skip(if: $skip1D) {
+          timestamp
+          value
+        }
+        priceHistory1W: priceHistory(duration: WEEK) @skip(if: $skip1W) {
+          timestamp
+          value
+        }
+        priceHistory1M: priceHistory(duration: MONTH) @skip(if: $skip1M) {
+          timestamp
+          value
+        }
+        priceHistory1Y: priceHistory(duration: YEAR) @skip(if: $skip1Y) {
+          timestamp
+          value
+        }
+      }
+    }
+  }
+`
+
 export type PricePoint = { value: number; timestamp: number }
 export function filterPrices(prices: NonNullable<NonNullable<SingleTokenData>['market']>['priceHistory'] | undefined) {
   return prices?.filter((p): p is PricePoint => Boolean(p && p.value))
@@ -130,44 +169,22 @@ export function useTokenQuery(
         current[originalTimePeriod] = filterPrices(token?.market?.priceHistory)
         return current
       }),
-    [token, originalTimePeriod]
+    [originalTimePeriod, token?.market?.priceHistory]
   )
 
   return [token, prices]
 }
 
-const tokenPriceQuery = graphql`
+// TODO: Return a QueryToken from useTokenQuery instead of SingleTokenData to make it more usable in Currency-centric interfaces.
-  query TokenPriceQuery(
+export class QueryToken extends WrappedTokenInfo {
-    $contract: ContractInput!
+  constructor(data: NonNullable<SingleTokenData>) {
-    $skip1H: Boolean!
+    super({
-    $skip1D: Boolean!
+      chainId: CHAIN_NAME_TO_CHAIN_ID[data.chain],
-    $skip1W: Boolean!
+      address: data.address,
-    $skip1M: Boolean!
+      decimals: data.decimals ?? DEFAULT_ERC20_DECIMALS,
-    $skip1Y: Boolean!
+      symbol: data.symbol ?? '',
-  ) {
+      name: data.name ?? '',
-    tokens(contracts: [$contract]) {
+      logoURI: data.project?.logoUrl ?? undefined,
-      market(currency: USD) {
+    })
-        priceHistory1H: priceHistory(duration: HOUR) @skip(if: $skip1H) {
-          timestamp
-          value
-        }
-        priceHistory1D: priceHistory(duration: DAY) @skip(if: $skip1D) {
-          timestamp
-          value
-        }
-        priceHistory1W: priceHistory(duration: WEEK) @skip(if: $skip1W) {
-          timestamp
-          value
-        }
-        priceHistory1M: priceHistory(duration: MONTH) @skip(if: $skip1M) {
-          timestamp
-          value
-        }
-        priceHistory1Y: priceHistory(duration: YEAR) @skip(if: $skip1Y) {
-          timestamp
-          value
-        }
-      }
-    }
   }
-`
+}

src/lib/hooks/useCurrency.ts

@@ -2,91 +2,17 @@ import { arrayify } from '@ethersproject/bytes'
 import { parseBytes32String } from '@ethersproject/strings'
 import { Currency, Token } from '@uniswap/sdk-core'
 import { useWeb3React } from '@web3-react/core'
-import ERC20_ABI from 'abis/erc20.json'
+import { isSupportedChain } from 'constants/chains'
-import { Erc20 } from 'abis/types'
-import { isSupportedChain, SupportedChainId } from 'constants/chains'
-import { RPC_PROVIDERS } from 'constants/providers'
 import { useBytes32TokenContract, useTokenContract } from 'hooks/useContract'
 import { NEVER_RELOAD, useSingleCallResult } from 'lib/hooks/multicall'
 import useNativeCurrency from 'lib/hooks/useNativeCurrency'
-import { useEffect, useMemo, useState } from 'react'
+import { useMemo } from 'react'
-import { WrappedTokenInfo } from 'state/lists/wrappedTokenInfo'
 
 import { DEFAULT_ERC20_DECIMALS } from '../../constants/tokens'
 import { TOKEN_SHORTHANDS } from '../../constants/tokens'
-import { getContract, isAddress } from '../../utils'
+import { isAddress } from '../../utils'
 import { supportedChainId } from '../../utils/supportedChainId'
 
-/**
- * Returns a Token from query data.
- * Data should already include all fields except decimals, or it will be considered invalid.
- * Returns null if the token is loading or null was passed.
- * Returns undefined if invalid or the token does not exist.
- */
-export function useTokenFromQuery({
-  address: tokenAddress,
-  chainId,
-  symbol,
-  name,
-  project,
-}: {
-  address?: string
-  chainId?: SupportedChainId
-  symbol?: string | null
-  name?: string | null
-  project?: { logoUrl?: string | null } | null
-} = {}): Token | null | undefined {
-  const { chainId: activeChainId } = useWeb3React()
-  const address = isAddress(tokenAddress)
-  const [decimals, setDecimals] = useState<number | null | undefined>(null)
-
-  const tokenContract = useTokenContract(chainId === activeChainId ? (address ? address : undefined) : undefined, false)
-  const { loading, result: [decimalsResult] = [] } = useSingleCallResult(
-    tokenContract,
-    'decimals',
-    undefined,
-    NEVER_RELOAD
-  )
-
-  useEffect(() => {
-    if (loading) {
-      setDecimals(null)
-    } else if (decimalsResult) {
-      setDecimals(decimalsResult)
-    } else if (!address || !chainId || chainId === activeChainId) {
-      setDecimals(undefined)
-    } else {
-      setDecimals(null)
-
-      // Load decimals from a cross-chain RPC provider.
-      const provider = RPC_PROVIDERS[chainId]
-      const contract = getContract(address, ERC20_ABI, provider) as Erc20
-      contract
-        .decimals()
-        .then((value) => {
-          if (!stale) setDecimals(value)
-        })
-        .catch(() => undefined)
-    }
-
-    let stale = false
-    return () => {
-      stale = true
-    }
-  }, [activeChainId, address, chainId, decimalsResult, loading])
-
-  return useMemo(() => {
-    if (!chainId || !address) return undefined
-    if (decimals === null || decimals === undefined) return decimals
-    if (!symbol || !name) {
-      return new Token(chainId, address, decimals, symbol ?? undefined, name ?? undefined)
-    } else {
-      const logoURI = project?.logoUrl ?? undefined
-      return new WrappedTokenInfo({ chainId, address, decimals, symbol, name, logoURI })
-    }
-  }, [address, chainId, decimals, name, project?.logoUrl, symbol])
-}
-
 // parse a name or symbol from a token response
 const BYTES32_REGEX = /^0x[a-fA-F0-9]{64}$/
 

src/pages/TokenDetails/index.tsx

@@ -1,4 +1,4 @@
-import { Currency } from '@uniswap/sdk-core'
+import { Currency, Token } from '@uniswap/sdk-core'
 import { PageName } from 'analytics/constants'
 import { Trace } from 'analytics/Trace'
 import { filterTimeAtom } from 'components/Tokens/state'
@@ -18,16 +18,15 @@ import StatsSection from 'components/Tokens/TokenDetails/StatsSection'
 import TokenSafetyMessage from 'components/TokenSafety/TokenSafetyMessage'
 import TokenSafetyModal from 'components/TokenSafety/TokenSafetyModal'
 import Widget from 'components/Widget'
-import { NATIVE_CHAIN_ID, nativeOnChain } from 'constants/tokens'
+import { DEFAULT_ERC20_DECIMALS, NATIVE_CHAIN_ID, nativeOnChain } from 'constants/tokens'
 import { checkWarning } from 'constants/tokenSafety'
 import { Chain } from 'graphql/data/__generated__/TokenQuery.graphql'
-import { useTokenQuery } from 'graphql/data/Token'
+import { QueryToken, useTokenQuery } from 'graphql/data/Token'
 import { CHAIN_NAME_TO_CHAIN_ID, validateUrlChainParam } from 'graphql/data/util'
 import { useIsUserAddedTokenOnChain } from 'hooks/Tokens'
 import { useOnGlobalChainSwitch } from 'hooks/useGlobalChainSwitch'
 import { useAtomValue } from 'jotai/utils'
-import { useTokenFromQuery } from 'lib/hooks/useCurrency'
+import { useCallback, useMemo, useState, useTransition } from 'react'
-import { useCallback, useState, useTransition } from 'react'
 import { ArrowLeft } from 'react-feather'
 import { useNavigate, useParams } from 'react-router-dom'
 
@@ -43,8 +42,12 @@ export default function TokenDetails() {
     chain,
     timePeriod
   )
-  const queryToken = useTokenFromQuery(isNative ? undefined : { ...tokenQueryData, chainId: pageChainId })
+  const token = useMemo(() => {
-  const token = isNative ? nativeCurrency : queryToken
+    if (!tokenAddress) return undefined
+    if (isNative) return nativeCurrency
+    if (tokenQueryData) return new QueryToken(tokenQueryData)
+    return new Token(pageChainId, tokenAddress, DEFAULT_ERC20_DECIMALS)
+  }, [isNative, nativeCurrency, pageChainId, tokenAddress, tokenQueryData])
 
   const tokenWarning = tokenAddress ? checkWarning(tokenAddress) : null
   const isBlockedToken = tokenWarning?.canProceed === false
@@ -129,7 +132,7 @@ export default function TokenDetails() {
 
         <RightPanel>
           <Widget
-            defaultToken={token === null ? undefined : token ?? nativeCurrency} // a null token is still loading, and should not be overridden.
+            defaultToken={token ?? nativeCurrency}
             onTokensChange={navigateToWidgetSelectedToken}
             onReviewSwapClick={onReviewSwapClick}
           />