feat: add slippage warning to MenuButton (#6548)

* feat: initial commit

* chore: add unit tests

* chore: move menubutton to sep. component

* chore: simplify styles and add real focused state

* chore: fix tests + some other tweaks

* chore: rename

* test: add snapshot tests

* tweaks

cypress/e2e/swap.test.ts

@@ -119,11 +119,11 @@ describe('Swap', () => {
     it('Opens and closes the settings menu', () => {
       cy.visit('/swap')
       cy.contains('Settings').should('not.exist')
-      cy.get(getTestSelector('swap-settings-button')).click()
+      cy.get(getTestSelector('open-settings-dialog-button')).click()
       cy.contains('Max slippage').should('exist')
       cy.contains('Transaction deadline').should('exist')
       cy.contains('Auto Router API').should('exist')
-      cy.get(getTestSelector('swap-settings-button')).click()
+      cy.get(getTestSelector('open-settings-dialog-button')).click()
       cy.contains('Settings').should('not.exist')
     })
 

src/components/Settings/MenuButton/index.test.tsx

@@ -0,0 +1,36 @@
+import { Percent } from '@uniswap/sdk-core'
+import { useUserSlippageTolerance } from 'state/user/hooks'
+import { SlippageTolerance } from 'state/user/types'
+import { mocked } from 'test-utils/mocked'
+import { render, screen } from 'test-utils/render'
+import { lightTheme } from 'theme/colors'
+import noop from 'utils/noop'
+
+import MenuButton from '.'
+
+jest.mock('state/user/hooks')
+
+const renderButton = () => {
+  render(<MenuButton disabled={false} onClick={noop} isActive={false} />)
+}
+
+describe('MenuButton', () => {
+  it('should render an icon when slippage is Auto', () => {
+    mocked(useUserSlippageTolerance).mockReturnValue([SlippageTolerance.Auto, noop])
+    renderButton()
+    expect(screen.queryByText('slippage')).not.toBeInTheDocument()
+  })
+  it('should render an icon with a custom slippage value', () => {
+    mocked(useUserSlippageTolerance).mockReturnValue([new Percent(5, 10_000), noop])
+    renderButton()
+    expect(screen.queryByText('0.05% slippage')).toBeInTheDocument()
+  })
+  it('should render an icon with a custom slippage and a warning when value is out of bounds', () => {
+    mocked(useUserSlippageTolerance).mockReturnValue([new Percent(1, 10_000), noop])
+    renderButton()
+    expect(screen.getByTestId('settings-icon-with-slippage')).toHaveStyleRule(
+      'background-color',
+      lightTheme.accentWarningSoft
+    )
+  })
+})

src/components/Settings/MenuButton/index.tsx

@@ -0,0 +1,91 @@
+import { t, Trans } from '@lingui/macro'
+import Row from 'components/Row'
+import { Settings } from 'react-feather'
+import { useUserSlippageTolerance } from 'state/user/hooks'
+import { SlippageTolerance } from 'state/user/types'
+import styled from 'styled-components/macro'
+import { ThemedText } from 'theme'
+import validateUserSlippageTolerance, { SlippageValidationResult } from 'utils/validateUserSlippageTolerance'
+
+const Icon = styled(Settings)`
+  height: 20px;
+  width: 20px;
+  > * {
+    stroke: ${({ theme }) => theme.textSecondary};
+  }
+`
+
+const Button = styled.button<{ isActive: boolean }>`
+  border: none;
+  background-color: transparent;
+  margin: 0;
+  padding: 0;
+  cursor: pointer;
+  outline: none;
+
+  :not([disabled]):hover {
+    opacity: 0.7;
+  }
+
+  ${({ isActive }) => isActive && `opacity: 0.7`}
+`
+
+const IconContainer = styled(Row)`
+  padding: 6px 12px;
+  border-radius: 16px;
+`
+
+const IconContainerWithSlippage = styled(IconContainer)<{ displayWarning?: boolean }>`
+  div {
+    color: ${({ theme, displayWarning }) => (displayWarning ? theme.accentWarning : theme.textSecondary)};
+  }
+
+  background-color: ${({ theme, displayWarning }) =>
+    displayWarning ? theme.accentWarningSoft : theme.backgroundModule};
+`
+
+const ButtonContent = () => {
+  const [userSlippageTolerance] = useUserSlippageTolerance()
+
+  if (userSlippageTolerance === SlippageTolerance.Auto) {
+    return (
+      <IconContainer>
+        <Icon />
+      </IconContainer>
+    )
+  }
+
+  const isInvalidSlippage = validateUserSlippageTolerance(userSlippageTolerance) !== SlippageValidationResult.Valid
+
+  return (
+    <IconContainerWithSlippage data-testid="settings-icon-with-slippage" gap="sm" displayWarning={isInvalidSlippage}>
+      <ThemedText.Caption>
+        <Trans>{userSlippageTolerance.toFixed(2)}% slippage</Trans>
+      </ThemedText.Caption>
+      <Icon />
+    </IconContainerWithSlippage>
+  )
+}
+
+export default function MenuButton({
+  disabled,
+  onClick,
+  isActive,
+}: {
+  disabled: boolean
+  onClick: () => void
+  isActive: boolean
+}) {
+  return (
+    <Button
+      disabled={disabled}
+      onClick={onClick}
+      isActive={isActive}
+      id="open-settings-dialog-button"
+      data-testid="open-settings-dialog-button"
+      aria-label={t`Transaction Settings`}
+    >
+      <ButtonContent />
+    </Button>
+  )
+}

src/components/Settings/index.tsx

@@ -1,5 +1,4 @@
 // eslint-disable-next-line no-restricted-imports
-import { t } from '@lingui/macro'
 import { Percent } from '@uniswap/sdk-core'
 import { useWeb3React } from '@web3-react/core'
 import { AutoColumn } from 'components/Column'
@@ -7,74 +6,38 @@ import { L2_CHAIN_IDS } from 'constants/chains'
 import { useOnClickOutside } from 'hooks/useOnClickOutside'
 import { isSupportedChainId } from 'lib/hooks/routing/clientSideSmartOrderRouter'
 import { useRef } from 'react'
-import { Settings } from 'react-feather'
 import { useModalIsOpen, useToggleSettingsMenu } from 'state/application/hooks'
 import { ApplicationModal } from 'state/application/reducer'
 import styled from 'styled-components/macro'
 
 import MaxSlippageSettings from './MaxSlippageSettings'
+import MenuButton from './MenuButton'
 import RouterPreferenceSettings from './RouterPreferenceSettings'
 import TransactionDeadlineSettings from './TransactionDeadlineSettings'
 
-const StyledMenuIcon = styled(Settings)`
-  height: 20px;
-  width: 20px;
-  > * {
-    stroke: ${({ theme }) => theme.textSecondary};
-  }
-`
-
-const StyledMenuButton = styled.button<{ disabled: boolean }>`
+const Menu = styled.div`
   position: relative;
-  width: 100%;
-  height: 100%;
-  border: none;
-  background-color: transparent;
-  margin: 0;
-  padding: 0;
-  border-radius: 0.5rem;
-  height: 20px;
-  ${({ disabled }) =>
-    !disabled &&
-    `
-    :hover,
-    :focus {
-      cursor: pointer;
-      outline: none;
-      opacity: 0.7;
-    }
-  `}
 `
 
-const StyledMenu = styled.div`
-  margin-left: 0.5rem;
-  display: flex;
-  justify-content: center;
-  align-items: center;
-  position: relative;
-  border: none;
-  text-align: left;
-`
-
-const MenuFlyout = styled.span`
+const MenuFlyout = styled(AutoColumn)`
   min-width: 20.125rem;
   background-color: ${({ theme }) => theme.backgroundSurface};
   border: 1px solid ${({ theme }) => theme.backgroundOutline};
   box-shadow: 0px 0px 1px rgba(0, 0, 0, 0.01), 0px 4px 8px rgba(0, 0, 0, 0.04), 0px 16px 24px rgba(0, 0, 0, 0.04),
     0px 24px 32px rgba(0, 0, 0, 0.01);
   border-radius: 12px;
-  display: flex;
-  flex-direction: column;
-  font-size: 1rem;
   position: absolute;
-  top: 2rem;
-  right: 0rem;
+  top: 100%;
+  margin-top: 10px;
+  right: 0;
   z-index: 100;
   color: ${({ theme }) => theme.textPrimary};
   ${({ theme }) => theme.deprecated_mediaWidth.deprecated_upToMedium`
     min-width: 18.125rem;
   `};
   user-select: none;
+  gap: 16px;
+  padding: 1rem;
 `
 
 const Divider = styled.div`
@@ -90,26 +53,19 @@ export default function SettingsTab({ autoSlippage }: { autoSlippage: Percent })
   const showDeadlineSettings = Boolean(chainId && !L2_CHAIN_IDS.includes(chainId))
 
   const node = useRef<HTMLDivElement | null>(null)
-  const open = useModalIsOpen(ApplicationModal.SETTINGS)
+  const isOpen = useModalIsOpen(ApplicationModal.SETTINGS)
 
-  const toggle = useToggleSettingsMenu()
-  useOnClickOutside(node, open ? toggle : undefined)
+  const toggleMenu = useToggleSettingsMenu()
+  useOnClickOutside(node, isOpen ? toggleMenu : undefined)
+
+  const isSupportedChain = isSupportedChainId(chainId)
 
   return (
-    <StyledMenu ref={node}>
-      <StyledMenuButton
-        disabled={!isSupportedChainId(chainId)}
-        onClick={toggle}
-        id="open-settings-dialog-button"
-        data-testid="open-settings-dialog-button"
-        aria-label={t`Transaction Settings`}
-      >
-        <StyledMenuIcon data-testid="swap-settings-button" />
-      </StyledMenuButton>
-      {open && (
+    <Menu ref={node}>
+      <MenuButton disabled={!isSupportedChain} isActive={isOpen} onClick={toggleMenu} />
+      {isOpen && (
         <MenuFlyout>
-          <AutoColumn gap="16px" style={{ padding: '1rem' }}>
-            {isSupportedChainId(chainId) && <RouterPreferenceSettings />}
+          <RouterPreferenceSettings />
           <Divider />
           <MaxSlippageSettings autoSlippage={autoSlippage} />
           {showDeadlineSettings && (
@@ -118,9 +74,8 @@ export default function SettingsTab({ autoSlippage }: { autoSlippage: Percent })
               <TransactionDeadlineSettings />
             </>
           )}
-          </AutoColumn>
         </MenuFlyout>
       )}
-    </StyledMenu>
+    </Menu>
   )
 }

src/components/swap/SwapHeader.tsx

@@ -1,28 +1,21 @@
 import { Trans } from '@lingui/macro'
 import { Percent } from '@uniswap/sdk-core'
 import { useFiatOnRampButtonEnabled } from 'featureFlags/flags/fiatOnRampButton'
-import { subhead } from 'nft/css/common.css'
 import styled from 'styled-components/macro'
+import { ThemedText } from 'theme'
 
 import { RowBetween, RowFixed } from '../Row'
 import SettingsTab from '../Settings'
 import SwapBuyFiatButton from './SwapBuyFiatButton'
 
-const StyledSwapHeader = styled.div`
-  padding: 8px 12px;
-  margin-bottom: 8px;
-  width: 100%;
+const StyledSwapHeader = styled(RowBetween)`
+  margin-bottom: 10px;
   color: ${({ theme }) => theme.textSecondary};
 `
 
-const TextHeader = styled.div`
-  color: ${({ theme }) => theme.textPrimary};
-  margin-right: 8px;
-  display: flex;
-  line-height: 20px;
-  flex-direction: row;
-  justify-content: center;
-  align-items: center;
+const HeaderButtonContainer = styled(RowFixed)`
+  padding: 0 12px;
+  gap: 16px;
 `
 
 export default function SwapHeader({ autoSlippage }: { autoSlippage: Percent }) {
@@ -30,17 +23,15 @@ export default function SwapHeader({ autoSlippage }: { autoSlippage: Percent })
 
   return (
     <StyledSwapHeader>
-      <RowBetween>
-        <RowFixed style={{ gap: '8px' }}>
-          <TextHeader className={subhead}>
+      <HeaderButtonContainer>
+        <ThemedText.SubHeader>
           <Trans>Swap</Trans>
-          </TextHeader>
+        </ThemedText.SubHeader>
         {fiatOnRampButtonEnabled && <SwapBuyFiatButton />}
-        </RowFixed>
+      </HeaderButtonContainer>
       <RowFixed>
         <SettingsTab autoSlippage={autoSlippage} />
       </RowFixed>
-      </RowBetween>
     </StyledSwapHeader>
   )
 }

src/components/swap/styleds.tsx

@@ -29,6 +29,7 @@ export const SwapWrapper = styled.main<{ chainId: number | undefined }>`
   border-radius: 16px;
   border: 1px solid ${({ theme }) => theme.backgroundOutline};
   padding: 8px;
+  padding-top: 12px;
   box-shadow: ${({ chainId }) => !!chainId && chainId === SupportedChainId.BNB && '0px 40px 120px 0px #f0b90b29'};
   z-index: ${Z_INDEX.default};
   transition: transform 250ms ease;

src/state/user/hooks.tsx

@@ -149,10 +149,16 @@ export function useUserSlippageTolerance(): [
     [dispatch]
   )
 
-  return useMemo(
-    () => [userSlippageTolerance, setUserSlippageTolerance],
-    [setUserSlippageTolerance, userSlippageTolerance]
-  )
+  return [userSlippageTolerance, setUserSlippageTolerance]
+}
+
+/**
+ *Returns user slippage tolerance, replacing the auto with a default value
+ * @param defaultSlippageTolerance the value to replace auto with
+ */
+export function useUserSlippageToleranceWithDefault(defaultSlippageTolerance: Percent): Percent {
+  const [allowedSlippage] = useUserSlippageTolerance()
+  return allowedSlippage === SlippageTolerance.Auto ? defaultSlippageTolerance : allowedSlippage
 }
 
 export function useUserHideClosedPositions(): [boolean, (newHideClosedPositions: boolean) => void] {
@@ -170,18 +176,6 @@ export function useUserHideClosedPositions(): [boolean, (newHideClosedPositions:
   return [hideClosedPositions, setHideClosedPositions]
 }
 
-/**
- * Same as above but replaces the auto with a default value
- * @param defaultSlippageTolerance the default value to replace auto with
- */
-export function useUserSlippageToleranceWithDefault(defaultSlippageTolerance: Percent): Percent {
-  const allowedSlippage = useUserSlippageTolerance()[0]
-  return useMemo(
-    () => (allowedSlippage === SlippageTolerance.Auto ? defaultSlippageTolerance : allowedSlippage),
-    [allowedSlippage, defaultSlippageTolerance]
-  )
-}
-
 export function useUserTransactionTTL(): [number, (slippage: number) => void] {
   const { chainId } = useWeb3React()
   const dispatch = useAppDispatch()

src/utils/validateUserSlippageTolerance.test.ts

@@ -0,0 +1,23 @@
+import { Percent } from '@uniswap/sdk-core'
+
+import validateUserSlippageTolerance, {
+  MAXIMUM_RECOMMENDED_SLIPPAGE,
+  MINIMUM_RECOMMENDED_SLIPPAGE,
+  SlippageValidationResult,
+} from './validateUserSlippageTolerance'
+
+describe('validateUserSlippageTolerance', () => {
+  it('should return warning when slippage is too low', () => {
+    expect(validateUserSlippageTolerance(new Percent(4, 10_000))).toBe(SlippageValidationResult.TooLow)
+  })
+  it('should return warning when slippage is too high', () => {
+    expect(validateUserSlippageTolerance(new Percent(2, 100))).toBe(SlippageValidationResult.TooHigh)
+  })
+  it('should not return warning when slippage is in bounds', () => {
+    expect(validateUserSlippageTolerance(new Percent(1, 100))).toBe(SlippageValidationResult.Valid)
+  })
+  it('should not return warning when slippage is equal to lower or upper bound', () => {
+    expect(validateUserSlippageTolerance(MINIMUM_RECOMMENDED_SLIPPAGE)).toBe(SlippageValidationResult.Valid)
+    expect(validateUserSlippageTolerance(MAXIMUM_RECOMMENDED_SLIPPAGE)).toBe(SlippageValidationResult.Valid)
+  })
+})

src/utils/validateUserSlippageTolerance.ts

@@ -0,0 +1,20 @@
+import { Percent } from '@uniswap/sdk-core'
+
+export enum SlippageValidationResult {
+  TooLow,
+  TooHigh,
+  Valid,
+}
+
+export const MINIMUM_RECOMMENDED_SLIPPAGE = new Percent(5, 10_000)
+export const MAXIMUM_RECOMMENDED_SLIPPAGE = new Percent(1, 100)
+
+export default function validateUserSlippageTolerance(userSlippageTolerance: Percent) {
+  if (userSlippageTolerance.lessThan(MINIMUM_RECOMMENDED_SLIPPAGE)) {
+    return SlippageValidationResult.TooLow
+  } else if (userSlippageTolerance.greaterThan(MAXIMUM_RECOMMENDED_SLIPPAGE)) {
+    return SlippageValidationResult.TooHigh
+  } else {
+    return SlippageValidationResult.Valid
+  }
+}