handle dismiss (#1328)

src/components/TokenWarningModal/index.tsx

 import { Token } from '@uniswap/sdk'
-import React, { useCallback } from 'react'
+import React from 'react'
 import Modal from '../Modal'
 import { ImportToken } from 'components/SearchModal/ImportToken'
 
 export default function TokenWarningModal({
   isOpen,
   tokens,
-  onConfirm
+  onConfirm,
+  onDismiss
 }: {
   isOpen: boolean
   tokens: Token[]
   onConfirm: () => void
+  onDismiss: () => void
 }) {
-  const handleDismiss = useCallback(() => null, [])
-
   return (
-    <Modal isOpen={isOpen} onDismiss={handleDismiss} maxHeight={90}>
+    <Modal isOpen={isOpen} onDismiss={onDismiss} maxHeight={100}>
       <ImportToken tokens={tokens} handleCurrencySelect={onConfirm} />
     </Modal>
   )

src/pages/Swap/index.tsx

@@ -48,8 +48,9 @@ import Loader from '../../components/Loader'
 import { useIsTransactionUnsupported } from 'hooks/Trades'
 import UnsupportedCurrencyFooter from 'components/swap/UnsupportedCurrencyFooter'
 import { isTradeBetter } from 'utils/trades'
+import { RouteComponentProps } from 'react-router-dom'
 
-export default function Swap() {
+export default function Swap({ history }: RouteComponentProps) {
   const loadedUrlParams = useDefaultsFromURLSearch()
 
   // token warning stuff
@@ -97,6 +98,7 @@ export default function Swap() {
     currencies,
     inputError: swapInputError
   } = useDerivedSwapInfo()
+
   const { wrapType, execute: onWrap, inputError: wrapInputError } = useWrapCallback(
     currencies[Field.INPUT],
     currencies[Field.OUTPUT],
@@ -142,6 +144,12 @@ export default function Swap() {
     [onUserInput]
   )
 
+  // reset if they close warning without tokens in params
+  const handleDismissTokenWarning = useCallback(() => {
+    setDismissTokenWarning(true)
+    history.push('/swap/')
+  }, [history])
+
   // modal and loading
   const [{ showConfirm, tradeToConfirm, swapErrorMessage, attemptingTxn, txHash }, setSwapState] = useState<{
     showConfirm: boolean
@@ -297,6 +305,7 @@ export default function Swap() {
         isOpen={importTokensNotInDefault.length > 0 && !dismissTokenWarning}
         tokens={importTokensNotInDefault}
         onConfirm={handleConfirmTokenWarning}
+        onDismiss={handleDismissTokenWarning}
       />
       <SwapPoolTabs active={'swap'} />
       <AppBody>