fix: add animated loading bars and ensure sorted tokens upon load (#3874)

* fix: add animated loading bars and ensure sorted tokens upon load

* refactor: undo refactor of token selector component in CurrencySearch

* fix: fix styling as per design, still need to respond to other comments in review

* fix: add timeout to token loader of 2 seconds

* fix: add snapshot test and styling changes as per fred rec

* refactor: simplify function in currency list test

* fix: increase loading bars time from 2 seconds to 3 sec

* fix: respond to zach's comments

* fix: fix import errors
Co-authored-by: Lynn Yu <lynn.yu@UNISWAP-MAC-015.local>

src/components/SearchModal/CurrencyList/__snapshots__/index.test.tsx.snap

+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`renders currency rows correctly when currencies list is non-empty 1`] = `
+<DocumentFragment>
+  <div
+    style="position: relative; height: 10px; width: 100%; overflow: auto; will-change: transform; direction: ltr;"
+  >
+    <div
+      style="height: 168px; width: 100%;"
+    >
+      <div
+        class="sc-bdnxRM Row-sc-u7azg8-0 Row__RowBetween-sc-u7azg8-1 styleds__MenuItem-sc-muzgnq-3 lmTMKd hLLNig hzJkYd firMKT token-item-0x6B175474E89094C44Da98b954EedeAC495271d0F"
+        style="position: absolute; left: 0px; top: 0px; height: 56px; width: 100%;"
+      >
+        CurrencyLogo currency=DAI
+        <div
+          class="Column-sc-1r2yyln-0 cYEAJI"
+        >
+          <div
+            class="css-8mokm4"
+            title="Dai Stablecoin"
+          >
+            DAI
+          </div>
+          <div
+            class="theme__TextWrapper-sc-5lu8um-0 gVIOIC css-165qfk5"
+          >
+            Dai Stablecoin
+          </div>
+        </div>
+        <span />
+      </div>
+      <div
+        class="sc-bdnxRM Row-sc-u7azg8-0 Row__RowBetween-sc-u7azg8-1 styleds__MenuItem-sc-muzgnq-3 lmTMKd hLLNig hzJkYd firMKT token-item-0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48"
+        style="position: absolute; left: 0px; top: 56px; height: 56px; width: 100%;"
+      >
+        CurrencyLogo currency=USDC
+        <div
+          class="Column-sc-1r2yyln-0 cYEAJI"
+        >
+          <div
+            class="css-8mokm4"
+            title="USD//C"
+          >
+            USDC
+          </div>
+          <div
+            class="theme__TextWrapper-sc-5lu8um-0 gVIOIC css-165qfk5"
+          >
+            USD//C
+          </div>
+        </div>
+        <span />
+      </div>
+      <div
+        class="sc-bdnxRM Row-sc-u7azg8-0 Row__RowBetween-sc-u7azg8-1 styleds__MenuItem-sc-muzgnq-3 lmTMKd hLLNig hzJkYd firMKT token-item-0x2260FAC5E5542a773Aa44fBCfeDf7C193bc2C599"
+        style="position: absolute; left: 0px; top: 112px; height: 56px; width: 100%;"
+      >
+        CurrencyLogo currency=WBTC
+        <div
+          class="Column-sc-1r2yyln-0 cYEAJI"
+        >
+          <div
+            class="css-8mokm4"
+            title="Wrapped BTC"
+          >
+            WBTC
+          </div>
+          <div
+            class="theme__TextWrapper-sc-5lu8um-0 gVIOIC css-165qfk5"
+          >
+            Wrapped BTC
+          </div>
+        </div>
+        <span />
+      </div>
+    </div>
+  </div>
+</DocumentFragment>
+`;
+
+exports[`renders loading rows when isLoading is true 1`] = `
+<DocumentFragment>
+  <div
+    style="position: relative; height: 10px; width: 100%; overflow: auto; will-change: transform; direction: ltr;"
+  >
+    <div
+      style="height: 0px; width: 100%;"
+    />
+  </div>
+</DocumentFragment>
+`;

src/components/SearchModal/CurrencyList/index.test.tsx

+import { Currency, CurrencyAmount as mockCurrencyAmount, Token as mockToken } from '@uniswap/sdk-core'
+import { DAI, USDC_MAINNET, WBTC } from 'constants/tokens'
+import * as mockJSBI from 'jsbi'
+import { render } from 'test-utils'
+
+import CurrencyList from '.'
+
+const noOp = function () {
+  // do nothing
+}
+
+const mockCurrencyAmt = {
+  [DAI.address]: mockCurrencyAmount.fromRawAmount(DAI, mockJSBI.default.BigInt(100)),
+  [USDC_MAINNET.address]: mockCurrencyAmount.fromRawAmount(USDC_MAINNET, mockJSBI.default.BigInt(10)),
+  [WBTC.address]: mockCurrencyAmount.fromRawAmount(WBTC, mockJSBI.default.BigInt(1)),
+}
+
+jest.mock(
+  'components/CurrencyLogo',
+  () =>
+    ({ currency }: { currency: Currency }) =>
+      `CurrencyLogo currency=${currency.symbol}`
+)
+
+jest.mock('hooks/useActiveWeb3React', () => {
+  return {
+    __esModule: true,
+    default: () => ({
+      account: '123',
+      active: true,
+    }),
+  }
+})
+
+jest.mock('../../../state/wallet/hooks', () => {
+  return {
+    useCurrencyBalance: (currency: Currency) => {
+      return mockCurrencyAmt[(currency as mockToken).address]
+    },
+  }
+})
+
+it('renders loading rows when isLoading is true', () => {
+  const { asFragment } = render(
+    <CurrencyList
+      height={10}
+      currencies={[]}
+      otherListTokens={[]}
+      selectedCurrency={null}
+      onCurrencySelect={noOp}
+      showImportView={noOp}
+      setImportToken={noOp}
+      isLoading={true}
+    />
+  )
+  expect(asFragment()).toMatchSnapshot()
+})
+
+it('renders currency rows correctly when currencies list is non-empty', () => {
+  const { asFragment } = render(
+    <CurrencyList
+      height={10}
+      currencies={[DAI, USDC_MAINNET, WBTC]}
+      otherListTokens={[]}
+      selectedCurrency={null}
+      onCurrencySelect={noOp}
+      showImportView={noOp}
+      setImportToken={noOp}
+      isLoading={false}
+    />
+  )
+  expect(asFragment()).toMatchSnapshot()
+})

src/components/SearchModal/CurrencyList.tsx → src/components/SearchModal/CurrencyList/index.tsx

@@ -9,20 +9,20 @@ import { FixedSizeList } from 'react-window'
 import { Text } from 'rebass'
 import styled from 'styled-components/macro'
 
-import TokenListLogo from '../../assets/svg/tokenlist.svg'
-import { useIsUserAddedToken } from '../../hooks/Tokens'
-import { useCombinedActiveList } from '../../state/lists/hooks'
-import { WrappedTokenInfo } from '../../state/lists/wrappedTokenInfo'
-import { useCurrencyBalance } from '../../state/wallet/hooks'
-import { ThemedText } from '../../theme'
-import { isTokenOnList } from '../../utils'
-import Column from '../Column'
-import CurrencyLogo from '../CurrencyLogo'
-import Loader from '../Loader'
-import { RowBetween, RowFixed } from '../Row'
-import { MouseoverTooltip } from '../Tooltip'
-import ImportRow from './ImportRow'
-import { MenuItem } from './styleds'
+import TokenListLogo from '../../../assets/svg/tokenlist.svg'
+import { useIsUserAddedToken } from '../../../hooks/Tokens'
+import { useCombinedActiveList } from '../../../state/lists/hooks'
+import { WrappedTokenInfo } from '../../../state/lists/wrappedTokenInfo'
+import { useCurrencyBalance } from '../../../state/wallet/hooks'
+import { ThemedText } from '../../../theme'
+import { isTokenOnList } from '../../../utils'
+import Column from '../../Column'
+import CurrencyLogo from '../../CurrencyLogo'
+import Loader from '../../Loader'
+import { RowBetween, RowFixed } from '../../Row'
+import { MouseoverTooltip } from '../../Tooltip'
+import ImportRow from '../ImportRow'
+import { LoadingRows, MenuItem } from '../styleds'
 
 function currencyKey(currency: Currency): string {
   return currency.isToken ? currency.address : 'ETHER'
@@ -195,6 +195,7 @@ export default function CurrencyList({
   showImportView,
   setImportToken,
   showCurrencyAmount,
+  isLoading,
 }: {
   height: number
   currencies: Currency[]
@@ -206,6 +207,7 @@ export default function CurrencyList({
   showImportView: () => void
   setImportToken: (token: Token) => void
   showCurrencyAmount?: boolean
+  isLoading: boolean
 }) {
   const itemData: (Currency | BreakLine)[] = useMemo(() => {
     if (otherListTokens && otherListTokens?.length > 0) {
@@ -232,7 +234,15 @@ export default function CurrencyList({
 
       const showImport = index > currencies.length
 
-      if (showImport && token) {
+      if (isLoading) {
+        return (
+          <LoadingRows>
+            <div />
+            <div />
+            <div />
+          </LoadingRows>
+        )
+      } else if (showImport && token) {
         return (
           <ImportRow style={style} token={token} showImportView={showImportView} setImportToken={setImportToken} dim />
         )
@@ -259,6 +269,7 @@ export default function CurrencyList({
       setImportToken,
       showImportView,
       showCurrencyAmount,
+      isLoading,
     ]
   )
 

src/components/SearchModal/CurrencySearch.tsx

@@ -74,6 +74,8 @@ export function CurrencySearch({
   const { chainId } = useActiveWeb3React()
   const theme = useTheme()
 
+  const [tokenLoaderTimerElapsed, setTokenLoaderTimerElapsed] = useState(false)
+
   // refs for fixed size lists
   const fixedList = useRef<FixedSizeList>()
 
@@ -103,10 +105,11 @@ export function CurrencySearch({
     return Object.values(allTokens).filter(getTokenFilter(debouncedQuery))
   }, [allTokens, debouncedQuery])
 
-  const balances = useAllTokenBalances()
+  const [balances, balancesIsLoading] = useAllTokenBalances()
   const sortedTokens: Token[] = useMemo(() => {
-    return filteredTokens.sort(tokenComparator.bind(null, balances))
-  }, [balances, filteredTokens])
+    void balancesIsLoading // creates a new array once balances load to update hooks
+    return [...filteredTokens].sort(tokenComparator.bind(null, balances))
+  }, [balances, filteredTokens, balancesIsLoading])
 
   const filteredSortedTokens = useSortTokensByQuery(debouncedQuery, sortedTokens)
 
@@ -173,6 +176,14 @@ export function CurrencySearch({
     filteredTokens.length === 0 || (debouncedQuery.length > 2 && !isAddressSearch) ? debouncedQuery : undefined
   )
 
+  // Timeout token loader after 3 seconds to avoid hanging in a loading state.
+  useEffect(() => {
+    const tokenLoaderTimer = setTimeout(() => {
+      setTokenLoaderTimerElapsed(true)
+    }, 3000)
+    return () => clearTimeout(tokenLoaderTimer)
+  }, [])
+
   return (
     <ContentWrapper>
       <PaddedColumn gap="16px">
@@ -218,6 +229,7 @@ export function CurrencySearch({
                 showImportView={showImportView}
                 setImportToken={setImportToken}
                 showCurrencyAmount={showCurrencyAmount}
+                isLoading={balancesIsLoading && !tokenLoaderTimerElapsed}
               />
             )}
           </AutoSizer>

src/components/SearchModal/styleds.tsx

+import { LoadingRows as BaseLoadingRows } from 'components/Loader/styled'
 import styled from 'styled-components/macro'
 
 import { AutoColumn } from '../Column'
@@ -72,3 +73,25 @@ export const SeparatorDark = styled.div`
   height: 1px;
   background-color: ${({ theme }) => theme.bg3};
 `
+
+export const LoadingRows = styled(BaseLoadingRows)`
+  grid-column-gap: 0.5em;
+  grid-template-columns: repeat(12, 1fr);
+  max-width: 960px;
+  padding: 12px 20px;
+
+  & > div:nth-child(4n + 1) {
+    grid-column: 1 / 8;
+    height: 1em;
+    margin-bottom: 0.25em;
+  }
+  & > div:nth-child(4n + 2) {
+    grid-column: 12;
+    height: 1em;
+    margin-top: 0.25em;
+  }
+  & > div:nth-child(4n + 3) {
+    grid-column: 1 / 4;
+    height: 0.75em;
+  }
+`

src/state/wallet/hooks.ts

 import { CurrencyAmount, Token } from '@uniswap/sdk-core'
 import useActiveWeb3React from 'hooks/useActiveWeb3React'
 import JSBI from 'jsbi'
-import { useTokenBalance, useTokenBalances } from 'lib/hooks/useCurrencyBalance'
+import { useTokenBalance, useTokenBalancesWithLoadingIndicator } from 'lib/hooks/useCurrencyBalance'
 import { useMemo } from 'react'
 
 import { UNI } from '../../constants/tokens'
@@ -19,12 +19,12 @@ export {
 } from 'lib/hooks/useCurrencyBalance'
 
 // mimics useAllBalances
-export function useAllTokenBalances(): { [tokenAddress: string]: CurrencyAmount<Token> | undefined } {
+export function useAllTokenBalances(): [{ [tokenAddress: string]: CurrencyAmount<Token> | undefined }, boolean] {
   const { account } = useActiveWeb3React()
   const allTokens = useAllTokens()
   const allTokensArray = useMemo(() => Object.values(allTokens ?? {}), [allTokens])
-  const balances = useTokenBalances(account ?? undefined, allTokensArray)
-  return balances ?? {}
+  const [balances, balancesIsLoading] = useTokenBalancesWithLoadingIndicator(account ?? undefined, allTokensArray)
+  return [balances ?? {}, balancesIsLoading]
 }
 
 // get the total owned, unclaimed, and unharvested UNI for account