Beta cleanup (#285)

* improve context logic

* fix font-variant

* add dependencies for later

* fix icon

.eslintrc

-{
-  "extends": "react-app"
-}

package.json

@@ -5,6 +5,7 @@
   "homepage": ".",
   "private": true,
   "dependencies": {
+    "@reach/tooltip": "^0.2.0",
     "classnames": "^2.2.6",
     "escape-string-regexp": "^2.0.0",
     "ethers": "^4.0.27",
@@ -12,15 +13,16 @@
     "i18next-browser-languagedetector": "^3.0.1",
     "i18next-xhr-backend": "^2.0.1",
     "jazzicon": "^1.5.0",
-    "lodash.merge": "^4.6.1",
     "node-sass": "^4.11.0",
     "react": "^16.8.6",
+    "react-aria-modal": "^4.0.0",
     "react-dom": "^16.8.6",
     "react-ga": "^2.5.7",
     "react-i18next": "^10.7.0",
     "react-router-dom": "^5.0.0",
-    "react-scripts": "^3.0.0",
+    "react-scripts": "^3.0.1",
     "react-transition-group": "1.x",
+    "styled-components": "^4.2.0",
     "ua-parser-js": "^0.7.18",
     "web3-react": "^5.0.4"
   },
@@ -40,14 +42,23 @@
     "check:format": "yarn format:base --check",
     "check:all": "yarn check:lint && yarn check:format"
   },
-  "license": "GPL-3.0-or-later",
-  "devDependencies": {
-    "prettier": "^1.17.0"
+  "eslintConfig": {
+    "extends": "react-app"
   },
-  "browserslist": [
+  "browserslist": {
+    "production": [
       ">0.2%",
       "not dead",
-    "not ie <= 11",
       "not op_mini all"
+    ],
+    "development": [
+      "last 1 chrome version",
+      "last 1 firefox version",
+      "last 1 safari version"
     ]
+  },
+  "license": "GPL-3.0-or-later",
+  "devDependencies": {
+    "prettier": "^1.17.0"
+  }
 }

src/components/CurrencyInputPanel/index.js

@@ -11,8 +11,8 @@ import { isAddress, calculateGasMargin } from '../../utils'
 import Modal from '../Modal'
 import TokenLogo from '../TokenLogo'
 import SearchIcon from '../../assets/images/magnifying-glass.svg'
-import { useTokenDetails, useAllTokenDetails } from '../../contexts/Static'
-import { useTransactionContext, usePendingApproval } from '../../contexts/Transaction'
+import { useTransactionAdder, usePendingApproval } from '../../contexts/Transactions'
+import { useTokenDetails, useAllTokenDetails } from '../../contexts/Tokens'
 
 import './currency-panel.scss'
 
@@ -43,7 +43,7 @@ export default function CurrencyInputPanel({
 
   const pendingApproval = usePendingApproval(selectedTokenAddress)
 
-  const { addTransaction } = useTransactionContext()
+  const addTransaction = useTransactionAdder()
   const inputRef = useRef()
 
   const allTokens = useAllTokenDetails()
@@ -74,7 +74,7 @@ export default function CurrencyInputPanel({
                   gasLimit: calculateGasMargin(estimatedGas, GAS_MARGIN)
                 })
                 .then(response => {
-                  addTransaction(response.hash, response)
+                  addTransaction(response)
                 })
             }}
           >

src/components/NavigationTabs/index.js

@@ -5,7 +5,7 @@ import { useTranslation } from 'react-i18next'
 import { useBodyKeyDown } from '../../hooks'
 
 import './navigation-tabs.scss'
-import { useApplicationContext } from '../../contexts/Application'
+import { useBetaMessageManager } from '../../contexts/Application'
 
 const tabOrder = [
   {
@@ -28,7 +28,7 @@ const tabOrder = [
 function NavigationTabs({ location: { pathname }, history }) {
   const { t } = useTranslation()
 
-  const { showBetaMessage, dismissBetaMessage } = useApplicationContext()
+  const [showBetaMessage, dismissBetaMessage] = useBetaMessageManager()
 
   const navigate = useCallback(
     direction => {

src/components/Web3Status/index.js

@@ -7,7 +7,7 @@ import { useTranslation } from 'react-i18next'
 import { ethers } from 'ethers'
 
 import Modal from '../Modal'
-import { useAllTransactions } from '../../contexts/Transaction'
+import { useAllTransactions } from '../../contexts/Transactions'
 
 import './web3-status.scss'
 
@@ -116,7 +116,15 @@ export default function Web3Status() {
             return
           } else {
             el.innerHTML = ''
-            el.appendChild(Jazzicon(16, parseInt(account.slice(2), 16)))
+            el.appendChild(
+              Jazzicon(
+                16,
+                ethers.utils
+                  .bigNumberify(account)
+                  .mod(Number.MAX_SAFE_INTEGER)
+                  .toNumber()
+              )
+            )
           }
         }}
       />

src/contexts/Allowances.js

+import React, { createContext, useContext, useReducer, useCallback, useMemo, useEffect } from 'react'
+import { useWeb3Context } from 'web3-react'
+
+import { safeAccess, isAddress, getTokenAllowance } from '../utils'
+import { useBlockNumber } from './Application'
+
+const UPDATE = 'UPDATE'
+
+const AllowancesContext = createContext()
+
+function useAllowancesContext() {
+  return useContext(AllowancesContext)
+}
+
+function reducer(state, { type, payload }) {
+  switch (type) {
+    case UPDATE: {
+      const { networkId, address, tokenAddress, spenderAddress, value, blockNumber } = payload
+      return {
+        ...state,
+        [networkId]: {
+          ...(safeAccess(state, [networkId]) || {}),
+          [address]: {
+            ...(safeAccess(state, [networkId, address]) || {}),
+            [tokenAddress]: {
+              ...(safeAccess(state, [networkId, address, tokenAddress]) || {}),
+              [spenderAddress]: {
+                value,
+                blockNumber
+              }
+            }
+          }
+        }
+      }
+    }
+    default: {
+      throw Error(`Unexpected action type in AllowancesContext reducer: '${type}'.`)
+    }
+  }
+}
+
+export default function Provider({ children }) {
+  const [state, dispatch] = useReducer(reducer, {})
+
+  const update = useCallback((networkId, address, tokenAddress, spenderAddress, value, blockNumber) => {
+    dispatch({ type: UPDATE, payload: { networkId, address, tokenAddress, spenderAddress, value, blockNumber } })
+  }, [])
+
+  const contextValue = useMemo(() => [state, { update }], [state, update])
+
+  return <AllowancesContext.Provider value={contextValue}>{children}</AllowancesContext.Provider>
+}
+
+export function useAddressAllowance(address, tokenAddress, spenderAddress) {
+  const { networkId, library } = useWeb3Context()
+
+  const globalBlockNumber = useBlockNumber()
+
+  const [state, { update }] = useAllowancesContext()
+  const { value, blockNumber } = safeAccess(state, [networkId, address, tokenAddress, spenderAddress]) || {}
+
+  useEffect(() => {
+    if (
+      isAddress(address) &&
+      isAddress(tokenAddress) &&
+      isAddress(spenderAddress) &&
+      (value === undefined || blockNumber !== globalBlockNumber) &&
+      (networkId || networkId === 0) &&
+      library
+    ) {
+      let stale = false
+
+      getTokenAllowance(address, tokenAddress, spenderAddress, library)
+        .then(value => {
+          if (!stale) {
+            update(networkId, address, tokenAddress, spenderAddress, value, globalBlockNumber)
+          }
+        })
+        .catch(() => {
+          if (!stale) {
+            update(networkId, address, tokenAddress, spenderAddress, null, globalBlockNumber)
+          }
+        })
+
+      return () => {
+        stale = true
+      }
+    }
+  }, [address, tokenAddress, spenderAddress, value, blockNumber, globalBlockNumber, networkId, library, update])
+
+  return value
+}

src/contexts/Application.js

-import React, { Component, createContext, useContext, useEffect } from 'react'
+import React, { createContext, useContext, useReducer, useCallback, useMemo, useEffect } from 'react'
 import { useWeb3Context } from 'web3-react'
+import { safeAccess } from '../utils'
 
-import { useBlockEffect } from '../hooks'
+const SHOW_BETA_MESSAGE = 'SHOW_BETA_MESSAGE'
+const BLOCK_NUMBERS = 'BLOCK_NUMBERS'
+
+const DISMISS_BETA_MESSAGE = 'DISMISS_BETA_MESSAGE'
+const UPDATE_BLOCK_NUMBER = 'UPDATE_BLOCK_NUMBER'
 
 const ApplicationContext = createContext()
 
-export default class Provider extends Component {
-  constructor(props) {
-    super(props)
+function useApplicationContext() {
+  return useContext(ApplicationContext)
+}
 
-    this.dismissBetaMessage = () => {
-      this.setState({ showBetaMessage: false })
+function reducer(state, { type, payload }) {
+  switch (type) {
+    case DISMISS_BETA_MESSAGE: {
+      return {
+        ...state,
+        [SHOW_BETA_MESSAGE]: false
       }
-
-    this.updateBlockNumber = blockNumber => {
-      this.setState({ blockNumber })
     }
-
-    this.state = {
-      showBetaMessage: true,
-      dismissBetaMessage: this.dismissBetaMessage,
-      blockNumber: undefined,
-      updateBlockNumber: this.updateBlockNumber
+    case UPDATE_BLOCK_NUMBER: {
+      const { networkId, blockNumber } = payload
+      return {
+        ...state,
+        [BLOCK_NUMBERS]: {
+          ...(safeAccess(state, [BLOCK_NUMBERS]) || {}),
+          [networkId]: blockNumber
         }
       }
-
-  render() {
-    return <ApplicationContext.Provider value={this.state}>{this.props.children}</ApplicationContext.Provider>
+    }
+    default: {
+      throw Error(`Unexpected action type in ApplicationContext reducer: '${type}'.`)
+    }
   }
 }
 
-export function useApplicationContext() {
-  return useContext(ApplicationContext)
+export default function Provider({ children }) {
+  const [state, dispatch] = useReducer(reducer, {
+    [SHOW_BETA_MESSAGE]: true,
+    [BLOCK_NUMBERS]: {}
+  })
+
+  const dismissBetaMessage = useCallback(() => {
+    dispatch({ type: DISMISS_BETA_MESSAGE })
+  }, [])
+  const updateBlockNumber = useCallback((networkId, blockNumber) => {
+    dispatch({ type: UPDATE_BLOCK_NUMBER, payload: { networkId, blockNumber } })
+  }, [])
+
+  const contextValue = useMemo(() => [state, { dismissBetaMessage, updateBlockNumber }], [
+    state,
+    dismissBetaMessage,
+    updateBlockNumber
+  ])
+
+  return <ApplicationContext.Provider value={contextValue}>{children}</ApplicationContext.Provider>
 }
 
 export function Updater() {
-  const { library } = useWeb3Context()
-  const { updateBlockNumber } = useApplicationContext()
+  const { networkId, library } = useWeb3Context()
+
+  const [, { updateBlockNumber }] = useApplicationContext()
 
-  // fetch the block number once on load...
   useEffect(() => {
-    if (library) {
+    if ((networkId || networkId === 0) && library) {
       let stale = false
 
+      function update() {
         library
           .getBlockNumber()
           .then(blockNumber => {
             if (!stale) {
-            updateBlockNumber(blockNumber)
+              updateBlockNumber(networkId, blockNumber)
             }
           })
           .catch(() => {
             if (!stale) {
-            updateBlockNumber(null)
+              updateBlockNumber(networkId, null)
             }
           })
+      }
+
+      update()
+      library.on('block', update)
 
       return () => {
         stale = true
-        // this clears block number on network change because the library has changed
-        updateBlockNumber(undefined)
+        library.removeListener('block', update)
       }
     }
-  }, [library, updateBlockNumber])
-
-  // ...and every block...
-  useBlockEffect(updateBlockNumber)
+  }, [networkId, library, updateBlockNumber])
 
   return null
 }
 
+export function useBetaMessageManager() {
+  const [state, { dismissBetaMessage }] = useApplicationContext()
+
+  return [safeAccess(state, [SHOW_BETA_MESSAGE]), dismissBetaMessage]
+}
+
 export function useBlockNumber() {
-  const { blockNumber } = useApplicationContext()
-  return blockNumber
+  const { networkId } = useWeb3Context()
+
+  const [state] = useApplicationContext()
+
+  return safeAccess(state, [BLOCK_NUMBERS, networkId])
 }

src/contexts/Balances.js

+import React, { createContext, useContext, useReducer, useCallback, useMemo, useEffect } from 'react'
+import { useWeb3Context } from 'web3-react'
+
+import { safeAccess, isAddress, getEtherBalance, getTokenBalance } from '../utils'
+import { useBlockNumber } from './Application'
+import { useTokenDetails } from './Tokens'
+
+const UPDATE = 'UPDATE'
+
+const BalancesContext = createContext()
+
+function useBalancesContext() {
+  return useContext(BalancesContext)
+}
+
+function reducer(state, { type, payload }) {
+  switch (type) {
+    case UPDATE: {
+      const { networkId, address, tokenAddress, value, blockNumber } = payload
+      return {
+        ...state,
+        [networkId]: {
+          ...(safeAccess(state, [networkId]) || {}),
+          [address]: {
+            ...(safeAccess(state, [networkId, address]) || {}),
+            [tokenAddress]: {
+              value,
+              blockNumber
+            }
+          }
+        }
+      }
+    }
+    default: {
+      throw Error(`Unexpected action type in BalancesContext reducer: '${type}'.`)
+    }
+  }
+}
+
+export default function Provider({ children }) {
+  const [state, dispatch] = useReducer(reducer, {})
+
+  const update = useCallback((networkId, address, tokenAddress, value, blockNumber) => {
+    dispatch({ type: UPDATE, payload: { networkId, address, tokenAddress, value, blockNumber } })
+  }, [])
+
+  const contextValue = useMemo(() => [state, { update }], [state, update])
+
+  return <BalancesContext.Provider value={contextValue}>{children}</BalancesContext.Provider>
+}
+
+export function useAddressBalance(address, tokenAddress) {
+  const { networkId, library } = useWeb3Context()
+
+  const globalBlockNumber = useBlockNumber()
+
+  const [state, { update }] = useBalancesContext()
+  const { value, blockNumber } = safeAccess(state, [networkId, address, tokenAddress]) || {}
+
+  useEffect(() => {
+    if (
+      isAddress(address) &&
+      (tokenAddress === 'ETH' || isAddress(tokenAddress)) &&
+      (value === undefined || blockNumber !== globalBlockNumber) &&
+      (networkId || networkId === 0) &&
+      library
+    ) {
+      let stale = false
+
+      ;(tokenAddress === 'ETH' ? getEtherBalance(address, library) : getTokenBalance(tokenAddress, address, library))
+        .then(value => {
+          if (!stale) {
+            update(networkId, address, tokenAddress, value, globalBlockNumber)
+          }
+        })
+        .catch(e => {
+          if (!stale) {
+            update(networkId, address, tokenAddress, null, globalBlockNumber)
+          }
+        })
+
+      return () => {
+        stale = true
+      }
+    }
+  }, [address, tokenAddress, value, blockNumber, globalBlockNumber, networkId, library, update])
+
+  return value
+}
+
+export function useExchangeReserves(tokenAddress) {
+  const { exchangeAddress } = useTokenDetails(tokenAddress)
+
+  const reserveETH = useAddressBalance(exchangeAddress, 'ETH')
+  const reserveToken = useAddressBalance(exchangeAddress, tokenAddress)
+
+  return { reserveETH, reserveToken }
+}

src/contexts/Block.js

-import React, { Component, createContext, useContext, useEffect } from 'react'
-import { useWeb3Context } from 'web3-react'
-import merge from 'lodash.merge'
-
-import { getEtherBalance, getTokenBalance, getTokenAllowance, isAddress } from '../utils'
-import { useBlockNumber } from './Application'
-import { useTokenDetails } from './Static'
-
-// define constants
-const BALANCE = 'balance'
-
-const ALLOWANCE = 'allowance'
-
-// node creation
-function createAddressValueNode(name, value, blockNumber) {
-  return { [name]: value, blockNumber }
-}
-
-// tree creation
-function createAddressBalanceTree(address, tokenAddress, value, blockNumber) {
-  return { [address]: { [tokenAddress]: createAddressValueNode(BALANCE, value, blockNumber) } }
-}
-
-function createAddressAllowanceTree(address, tokenAddress, spenderAddress, value, blockNumber) {
-  return {
-    [address]: { [tokenAddress]: { [spenderAddress]: createAddressValueNode(ALLOWANCE, value, blockNumber) } }
-  }
-}
-
-// create contexts
-const AddressBalanceContext = createContext()
-
-const AddressAllowanceContext = createContext()
-
-// define providers
-class AddressBalanceContextProvider extends Component {
-  constructor(props) {
-    super(props)
-
-    this.getValue = (address, tokenAddress) => {
-      return this.state[BALANCE][address] && this.state[BALANCE][address][tokenAddress]
-        ? this.state[BALANCE][address][tokenAddress]
-        : createAddressValueNode(BALANCE)
-    }
-
-    this.updateValue = (address, tokenAddress, value, blockNumber) => {
-      this.setState(state => ({
-        [BALANCE]: merge(state[BALANCE], createAddressBalanceTree(address, tokenAddress, value, blockNumber))
-      }))
-    }
-
-    this.clearValues = () => {
-      this.setState({ [BALANCE]: {} })
-    }
-
-    this.state = {
-      [BALANCE]: {},
-      getValue: this.getValue,
-      updateValue: this.updateValue,
-      clearValues: this.clearValues
-    }
-  }
-
-  render() {
-    return <AddressBalanceContext.Provider value={this.state}>{this.props.children}</AddressBalanceContext.Provider>
-  }
-}
-
-class AddressAllowanceContextProvider extends Component {
-  constructor(props) {
-    super(props)
-
-    this.getValue = (address, tokenAddress, spenderAddress) => {
-      return this.state[ALLOWANCE][address] &&
-        this.state[ALLOWANCE][address][tokenAddress] &&
-        this.state[ALLOWANCE][address][tokenAddress][spenderAddress]
-        ? this.state[ALLOWANCE][address][tokenAddress][spenderAddress]
-        : createAddressValueNode(ALLOWANCE)
-    }
-
-    this.updateValue = (address, tokenAddress, spenderAddress, value, blockNumber) => {
-      this.setState(state => ({
-        [ALLOWANCE]: merge(
-          state[ALLOWANCE],
-          createAddressAllowanceTree(address, tokenAddress, spenderAddress, value, blockNumber)
-        )
-      }))
-    }
-
-    this.clearValues = () => {
-      this.setState({ [ALLOWANCE]: {} })
-    }
-
-    this.state = {
-      [ALLOWANCE]: {},
-      getValue: this.getValue,
-      updateValue: this.updateValue,
-      clearValues: this.clearValues
-    }
-  }
-
-  render() {
-    return <AddressAllowanceContext.Provider value={this.state}>{this.props.children}</AddressAllowanceContext.Provider>
-  }
-}
-
-export default function Provider({ children }) {
-  return (
-    <AddressBalanceContextProvider>
-      <AddressAllowanceContextProvider>{children}</AddressAllowanceContextProvider>
-    </AddressBalanceContextProvider>
-  )
-}
-
-// define useContext wrappers
-function useAddressBalanceContext() {
-  return useContext(AddressBalanceContext)
-}
-
-function useAddressAllowanceContext() {
-  return useContext(AddressAllowanceContext)
-}
-
-export function Updater() {
-  const { networkId } = useWeb3Context()
-
-  const { clearValues: clearValuesBalance } = useAddressBalanceContext()
-  const { clearValues: clearValuesAllowance } = useAddressAllowanceContext()
-
-  useEffect(() => {
-    return () => {
-      clearValuesBalance()
-      clearValuesAllowance()
-    }
-  }, [clearValuesBalance, clearValuesAllowance, networkId])
-
-  return null
-}
-
-// define custom hooks
-export function useAddressBalance(address, tokenAddress) {
-  const { library } = useWeb3Context()
-
-  const globalBlockNumber = useBlockNumber()
-
-  const { getValue, updateValue } = useAddressBalanceContext()
-  const { [BALANCE]: balance, blockNumber: balanceUpdatedBlockNumber } = getValue(address, tokenAddress)
-
-  useEffect(() => {
-    // gate this entire effect by checking that the inputs are valid
-    if (isAddress(address) && (tokenAddress === 'ETH' || isAddress(tokenAddress))) {
-      // if they are, and the balance is undefined or stale, fetch it
-      if (balance === undefined || balanceUpdatedBlockNumber !== globalBlockNumber) {
-        let stale = false
-        ;(tokenAddress === 'ETH' ? getEtherBalance(address, library) : getTokenBalance(tokenAddress, address, library))
-          .then(value => {
-            if (!stale) {
-              updateValue(address, tokenAddress, value, globalBlockNumber)
-            }
-          })
-          .catch(() => {
-            if (!stale) {
-              updateValue(address, tokenAddress, null, globalBlockNumber)
-            }
-          })
-        return () => {
-          stale = true
-        }
-      }
-    }
-  }, [address, tokenAddress, balance, balanceUpdatedBlockNumber, globalBlockNumber, library, updateValue])
-
-  return balance
-}
-
-export function useAddressAllowance(address, tokenAddress, spenderAddress) {
-  const { library } = useWeb3Context()
-
-  const globalBlockNumber = useBlockNumber()
-
-  const { getValue, updateValue } = useAddressAllowanceContext()
-  const { [ALLOWANCE]: allowance, blockNumber: allowanceUpdatedBlockNumber } = getValue(
-    address,
-    tokenAddress,
-    spenderAddress
-  )
-
-  useEffect(() => {
-    // gate this entire effect by checking that the inputs are valid
-    if (isAddress(address) && isAddress(tokenAddress) && isAddress(spenderAddress)) {
-      // if they are, and the balance is undefined or stale, fetch it
-      if (allowance === undefined || allowanceUpdatedBlockNumber !== globalBlockNumber) {
-        let stale = false
-        getTokenAllowance(address, tokenAddress, spenderAddress, library)
-          .then(value => {
-            if (!stale) {
-              updateValue(address, tokenAddress, spenderAddress, value, globalBlockNumber)
-            }
-          })
-          .catch(() => {
-            if (!stale) {
-              updateValue(address, tokenAddress, spenderAddress, null, globalBlockNumber)
-            }
-          })
-        return () => {
-          stale = true
-        }
-      }
-    }
-  }, [
-    address,
-    tokenAddress,
-    spenderAddress,
-    allowance,
-    allowanceUpdatedBlockNumber,
-    globalBlockNumber,
-    library,
-    updateValue
-  ])
-
-  return allowance
-}
-
-export function useExchangeReserves(tokenAddress) {
-  const { exchangeAddress } = useTokenDetails(tokenAddress)
-
-  const reserveETH = useAddressBalance(exchangeAddress, 'ETH')
-  const reserveToken = useAddressBalance(exchangeAddress, tokenAddress)
-
-  return { reserveETH, reserveToken }
-}

src/contexts/Transaction.js

-import React, { Component, createContext, useContext, useCallback, useEffect } from 'react'
-import { useWeb3Context } from 'web3-react'
-import { ethers } from 'ethers'
-import merge from 'lodash.merge'
-
-import { useBlockEffect } from '../hooks'
-
-const TRANSACTION = 'transaction'
-
-const RESPONSE = 'response'
-const COMPLETED = 'completed'
-const RECEIPT = 'receipt'
-
-const TransactionContext = createContext()
-
-function removeUndefinedValues(o) {
-  return Object.keys(o)
-    .filter(k => o[k] !== undefined)
-    .reduce((innerO, k) => {
-      innerO[k] = o[k]
-      return innerO
-    }, {})
-}
-
-function createTransactionNode(response, completed, receipt, noUndefinedValues) {
-  const node = { [RESPONSE]: response, [COMPLETED]: completed, [RECEIPT]: receipt }
-  return noUndefinedValues ? removeUndefinedValues(node) : node
-}
-
-// tree creation
-function createTokenDetailTree(hash, response, completed, receipt, noUndefinedValues = false) {
-  return { [hash]: createTransactionNode(response, completed, receipt, noUndefinedValues) }
-}
-
-export default class Provider extends Component {
-  constructor(props) {
-    super(props)
-
-    this.getTransactions = () => {
-      return this.state[TRANSACTION]
-    }
-
-    this.addTransaction = (hash, response) => {
-      this.setState(state => ({
-        [TRANSACTION]: merge(state[TRANSACTION], createTokenDetailTree(hash, response, false))
-      }))
-    }
-
-    this.updateTransaction = (hash, receipt) => {
-      this.setState(state => ({
-        [TRANSACTION]: merge(state[TRANSACTION], createTokenDetailTree(hash, undefined, true, receipt, true))
-      }))
-    }
-
-    this.clearTransactions = () => {
-      this.setState({ [TRANSACTION]: {} })
-    }
-
-    this.state = {
-      [TRANSACTION]: {},
-      getTransactions: this.getTransactions,
-      addTransaction: this.addTransaction,
-      updateTransaction: this.updateTransaction,
-      clearTransactions: this.clearTransactions
-    }
-  }
-
-  render() {
-    return <TransactionContext.Provider value={this.state}>{this.props.children}</TransactionContext.Provider>
-  }
-}
-
-export function useTransactionContext() {
-  return useContext(TransactionContext)
-}
-
-export function Updater() {
-  const { library, networkId } = useWeb3Context()
-
-  const { getTransactions, updateTransaction, clearTransactions } = useTransactionContext()
-
-  useEffect(() => {
-    return () => {
-      clearTransactions()
-    }
-  }, [clearTransactions, networkId])
-
-  const updateTransactionHashes = useCallback(() => {
-    if (library) {
-      const transactions = getTransactions()
-      Object.keys(transactions)
-        .filter(k => !transactions[k][COMPLETED])
-        .forEach(hash => {
-          library.getTransactionReceipt(hash).then(receipt => {
-            if (receipt) {
-              updateTransaction(hash, receipt)
-            }
-          })
-        })
-    }
-  }, [library, getTransactions, updateTransaction])
-
-  useBlockEffect(updateTransactionHashes)
-
-  return null
-}
-
-export function useAllTransactions() {
-  const { getTransactions } = useTransactionContext()
-
-  return getTransactions()
-}
-
-export function usePendingApproval(tokenAddress) {
-  const allTransactions = useAllTransactions()
-
-  return (
-    Object.keys(allTransactions).filter(hash => {
-      const transaction = allTransactions[hash]
-      if (
-        transaction.completed ||
-        transaction.response.to !== tokenAddress ||
-        transaction.response.data.substring(0, 10) !== ethers.utils.id('approve(address,uint256)').substring(0, 10)
-      ) {
-        return false
-      } else {
-        return true
-      }
-    }).length >= 1
-  )
-}

src/contexts/Transactions.js

+import React, { createContext, useContext, useReducer, useCallback, useMemo, useEffect } from 'react'
+import { useWeb3Context } from 'web3-react'
+import { ethers } from 'ethers'
+
+import { safeAccess } from '../utils'
+import { useBlockNumber } from './Application'
+
+const RESPONSE = 'response'
+const BLOCK_NUMBER_CHECKED = 'BLOCK_NUMBER_CHECKED'
+const RECEIPT = 'receipt'
+
+const ADD = 'ADD'
+const CHECK = 'CHECK'
+const FINALIZE = 'FINALIZE'
+
+const TransactionsContext = createContext()
+
+export function useTransactionsContext() {
+  return useContext(TransactionsContext)
+}
+
+function reducer(state, { type, payload }) {
+  switch (type) {
+    case ADD: {
+      const { networkId, hash, response } = payload
+
+      if (safeAccess(state, [networkId, hash]) !== null) {
+        throw Error('Attempted to add existing transaction.')
+      }
+
+      return {
+        ...state,
+        [networkId]: {
+          ...(safeAccess(state, [networkId]) || {}),
+          [hash]: {
+            [RESPONSE]: response
+          }
+        }
+      }
+    }
+    case CHECK: {
+      const { networkId, hash, blockNumber } = payload
+
+      if (safeAccess(state, [networkId, hash]) === null) {
+        throw Error('Attempted to check non-existent transaction.')
+      }
+
+      return {
+        ...state,
+        [networkId]: {
+          ...(safeAccess(state, [networkId]) || {}),
+          [hash]: {
+            ...(safeAccess(state, [networkId, hash]) || {}),
+            [BLOCK_NUMBER_CHECKED]: blockNumber
+          }
+        }
+      }
+    }
+    case FINALIZE: {
+      const { networkId, hash, receipt } = payload
+
+      if (safeAccess(state, [networkId, hash]) === null) {
+        throw Error('Attempted to finalize non-existent transaction.')
+      }
+
+      return {
+        ...state,
+        [networkId]: {
+          ...(safeAccess(state, [networkId]) || {}),
+          [hash]: {
+            ...(safeAccess(state, [networkId, hash]) || {}),
+            [RECEIPT]: receipt
+          }
+        }
+      }
+    }
+    default: {
+      throw Error(`Unexpected action type in TransactionsContext reducer: '${type}'.`)
+    }
+  }
+}
+
+export default function Provider({ children }) {
+  const [state, dispatch] = useReducer(reducer, {})
+
+  const add = useCallback((networkId, hash, response) => {
+    dispatch({ type: ADD, payload: { networkId, hash, response } })
+  }, [])
+  const check = useCallback((networkId, hash, blockNumber) => {
+    dispatch({ type: ADD, payload: { networkId, hash, blockNumber } })
+  }, [])
+  const finalize = useCallback((networkId, hash, receipt) => {
+    dispatch({ type: FINALIZE, payload: { networkId, hash, receipt } })
+  }, [])
+
+  const contextValue = useMemo(() => [state, { add, check, finalize }], [state, add, check, finalize])
+
+  return <TransactionsContext.Provider value={contextValue}>{children}</TransactionsContext.Provider>
+}
+
+export function Updater() {
+  const { networkId, library } = useWeb3Context()
+
+  const globalBlockNumber = useBlockNumber()
+
+  const [state, { check, finalize }] = useTransactionsContext()
+
+  useEffect(() => {
+    if ((networkId || networkId === 0) && library) {
+      const allTransactions = safeAccess(state, [networkId]) || {}
+      const allUncheckedTransactions = Object.keys(allTransactions).filter(
+        hash => !allTransactions[hash][RECEIPT] && allTransactions[hash][BLOCK_NUMBER_CHECKED] !== globalBlockNumber
+      )
+
+      let stale = false
+      Object.keys(allUncheckedTransactions).forEach(hash => {
+        library
+          .getTransactionReceipt(hash)
+          .then(receipt => {
+            if (!stale) {
+              if (!receipt) {
+                check(networkId, hash, globalBlockNumber)
+              } else {
+                finalize(networkId, hash, receipt)
+              }
+            }
+          })
+          .catch(() => {
+            check(networkId, hash, globalBlockNumber)
+          })
+      })
+
+      return () => {
+        stale = true
+      }
+    }
+  }, [networkId, library, state, globalBlockNumber, check, finalize])
+
+  return null
+}
+
+export function useTransactionAdder() {
+  const { networkId } = useWeb3Context()
+
+  const [, { add }] = useTransactionsContext()
+
+  return useCallback(
+    response => {
+      if (!(networkId || networkId === 0)) {
+        throw Error(`Invalid networkId '${networkId}`)
+      }
+
+      const hash = safeAccess(response, ['hash'])
+
+      if (!hash) {
+        throw Error('No transaction hash found.')
+      }
+
+      add(networkId, hash, response)
+    },
+    [networkId, add]
+  )
+}
+
+export function useAllTransactions() {
+  const { networkId } = useWeb3Context()
+
+  const [state] = useTransactionsContext()
+
+  return safeAccess(state, [networkId]) || {}
+}
+
+export function usePendingApproval(tokenAddress) {
+  const allTransactions = useAllTransactions()
+
+  return (
+    Object.keys(allTransactions).filter(hash => {
+      if (
+        allTransactions[hash][RECEIPT] ||
+        allTransactions[hash][RESPONSE].to !== tokenAddress ||
+        allTransactions[hash][RESPONSE].data.substring(0, 10) !==
+          ethers.utils.id('approve(address,uint256)').substring(0, 10)
+      ) {
+        return false
+      } else {
+        return true
+      }
+    }).length >= 1
+  )
+}

src/hooks/index.js

@@ -23,22 +23,6 @@ export function useBodyKeyDown(targetKey, onKeyDown, suppressOnKeyDown = false)
   }, [downHandler])
 }
 
-export function useBlockEffect(functionToRun) {
-  const { library } = useWeb3Context()
-
-  useEffect(() => {
-    if (library) {
-      function wrappedEffect(blockNumber) {
-        functionToRun(blockNumber)
-      }
-      library.on('block', wrappedEffect)
-      return () => {
-        library.removeListener('block', wrappedEffect)
-      }
-    }
-  }, [library, functionToRun])
-}
-
 // returns null on errors
 export function useContract(address, ABI, withSignerIfPossible = true) {
   const { library, account } = useWeb3Context()

src/index.js

@@ -2,14 +2,16 @@ import React from 'react'
 import ReactDOM from 'react-dom'
 import ReactGA from 'react-ga'
 import Web3Provider, { Connectors } from 'web3-react'
+
+import ThemeProvider, { GlobalStyle } from './theme'
 import ApplicationContextProvider, { Updater as ApplicationContextUpdater } from './contexts/Application'
-import TransactionContextProvider, { Updater as TransactionUpdater } from './contexts/Transaction'
-import StaticContextProvider, { Updater as StaticContextUpdater } from './contexts/Static'
-import BlockContextProvider, { Updater as BlockContextUpdater } from './contexts/Block'
+import TransactionContextProvider, { Updater as TransactionContextUpdater } from './contexts/Transactions'
+import TokensContextProvider from './contexts/Tokens'
+import BalancesContextProvider from './contexts/Balances'
+import AllowancesContextProvider from './contexts/Allowances'
 
 import App from './pages/App'
 
-import './index.scss'
 import './i18n'
 
 if (process.env.NODE_ENV === 'production') {
@@ -30,9 +32,11 @@ function ContextProviders({ children }) {
   return (
     <ApplicationContextProvider>
       <TransactionContextProvider>
-        <StaticContextProvider>
-          <BlockContextProvider>{children}</BlockContextProvider>
-        </StaticContextProvider>
+        <TokensContextProvider>
+          <BalancesContextProvider>
+            <AllowancesContextProvider>{children}</AllowancesContextProvider>
+          </BalancesContextProvider>
+        </TokensContextProvider>
       </TransactionContextProvider>
     </ApplicationContextProvider>
   )
@@ -42,19 +46,22 @@ function Updaters() {
   return (
     <>
       <ApplicationContextUpdater />
-      <TransactionUpdater />
-      <StaticContextUpdater />
-      <BlockContextUpdater />
+      <TransactionContextUpdater />
     </>
   )
 }
 
 ReactDOM.render(
+  <ThemeProvider>
+    <>
+      <GlobalStyle />
       <Web3Provider connectors={connectors} libraryName="ethers.js">
         <ContextProviders>
           <Updaters />
           <App />
         </ContextProviders>
-  </Web3Provider>,
+      </Web3Provider>
+    </>
+  </ThemeProvider>,
   document.getElementById('root')
 )

src/index.scss

-@import url('https://rsms.me/inter/inter.css');
-@import './variables.scss';
-
-html,
-body {
-  margin: 0;
-  padding: 0;
-  font-family: 'Inter UI', sans-serif;
-  font-size: 16px;
-  -webkit-font-smoothing: antialiased;
-  -moz-osx-font-smoothing: grayscale;
-  overflow-x: hidden;
-}
-
-#root {
-  position: relative;
-  display: flex;
-  flex-flow: column nowrap;
-  height: 100vh;
-  width: 100vw;
-  overflow-x: hidden;
-  overflow-y: auto;
-  background-color: $white;
-  z-index: 100;
-  -webkit-tap-highlight-color: rgba(255, 255, 255, 0);
-  @media only screen and (min-width: 768px) {
-    justify-content: center;
-    align-items: center;
-  }
-}
-
-#modal-root {
-  position: fixed;
-  top: 0;
-  left: 0;
-  right: 0;
-  z-index: 200;
-}
-
-.loader {
-  border: 1px solid transparent; /* Light grey */
-  border-top: 1px solid $royal-blue; /* Blue */
-  border-radius: 50%;
-  width: 0.75rem;
-  height: 0.75rem;
-  margin-right: 0.25rem;
-  animation: spin 1s cubic-bezier(0.25, 0.46, 0.45, 0.94) infinite;
-}
-
-@keyframes spin {
-  0% {
-    transform: rotate(0deg);
-  }
-  100% {
-    transform: rotate(360deg);
-  }
-}

src/pages/Pool/AddLiquidity.js

@@ -10,13 +10,14 @@ import OversizedPanel from '../../components/OversizedPanel'
 import ContextualInfo from '../../components/ContextualInfo'
 import PlusBlue from '../../assets/images/plus-blue.svg'
 import PlusGrey from '../../assets/images/plus-grey.svg'
-import { useBlockEffect, useExchangeContract } from '../../hooks'
+import { useExchangeContract } from '../../hooks'
 import { amountFormatter, calculateGasMargin } from '../../utils'
-import { useTokenDetails } from '../../contexts/Static'
-import { useAddressBalance, useExchangeReserves, useAddressAllowance } from '../../contexts/Block'
+import { useTransactionAdder } from '../../contexts/Transactions'
+import { useTokenDetails } from '../../contexts/Tokens'
+import { useAddressBalance, useExchangeReserves } from '../../contexts/Balances'
+import { useAddressAllowance } from '../../contexts/Allowances'
 
 import './pool.scss'
-import { useTransactionContext } from '../../contexts/Transaction'
 
 const INPUT = 0
 const OUTPUT = 1
@@ -117,7 +118,7 @@ function getMarketRate(reserveETH, reserveToken, decimals, invert = false) {
 
 export default function AddLiquidity() {
   const { t } = useTranslation()
-  const { active, account } = useWeb3Context()
+  const { library, active, account } = useWeb3Context()
 
   const [addLiquidityState, dispatchAddLiquidityState] = useReducer(addLiquidityStateReducer, initialAddLiquidityState)
   const { inputValue, outputValue, lastEditedField, outputCurrency } = addLiquidityState
@@ -141,8 +142,12 @@ export default function AddLiquidity() {
   }, [exchangeContract])
   useEffect(() => {
     fetchPoolTokens()
-  }, [fetchPoolTokens])
-  useBlockEffect(fetchPoolTokens)
+    library.on('block', fetchPoolTokens)
+
+    return () => {
+      library.removeListener('block', fetchPoolTokens)
+    }
+  }, [fetchPoolTokens, library])
 
   const poolTokenBalance = useAddressBalance(account, exchangeAddress)
   const exchangeETHBalance = useAddressBalance(exchangeAddress, 'ETH')
@@ -279,7 +284,7 @@ export default function AddLiquidity() {
     )
   }
 
-  const { addTransaction } = useTransactionContext()
+  const addTransaction = useTransactionAdder()
 
   const isActive = active && account
   const isValid = inputError === null || outputError === null
@@ -311,7 +316,7 @@ export default function AddLiquidity() {
         }
       )
       .then(response => {
-        addTransaction(response.hash, response)
+        addTransaction(response)
       })
   }
 
@@ -333,7 +338,6 @@ export default function AddLiquidity() {
     }
   }, [decimals, inputValue, isNewExchange, outputValue])
 
-  console.log('rendering')
   // parse input value
   useEffect(() => {
     if (isNewExchange === false && inputValue && marketRate && lastEditedField === INPUT) {

src/pages/Pool/CreateExchange.js

@@ -8,9 +8,9 @@ import ReactGA from 'react-ga'
 
 import AddressInputPanel from '../../components/AddressInputPanel'
 import OversizedPanel from '../../components/OversizedPanel'
-import { useTokenDetails } from '../../contexts/Static'
-import { useTransactionContext } from '../../contexts/Transaction'
 import { useFactoryContract } from '../../hooks'
+import { useTokenDetails } from '../../contexts/Tokens'
+import { useTransactionAdder } from '../../contexts/Transactions'
 
 function CreateExchange({ history, location }) {
   const { t } = useTranslation()
@@ -24,7 +24,7 @@ function CreateExchange({ history, location }) {
   const [tokenAddressError, setTokenAddressError] = useState()
 
   const { name, symbol, decimals, exchangeAddress } = useTokenDetails(tokenAddress.address)
-  const { addTransaction } = useTransactionContext()
+  const addTransaction = useTransactionAdder()
 
   // clear location state, if it exists
   useEffect(() => {
@@ -61,11 +61,12 @@ function CreateExchange({ history, location }) {
     const estimatedGasLimit = await factory.estimate.createExchange(tokenAddress.address)
 
     factory.createExchange(tokenAddress.address, { gasLimit: estimatedGasLimit }).then(response => {
-      addTransaction(response.hash, response)
       ReactGA.event({
         category: 'Pool',
         action: 'CreateExchange'
       })
+
+      addTransaction(response)
     })
   }
 

src/pages/Pool/RemoveLiquidity.js

@@ -10,11 +10,11 @@ import ContextualInfo from '../../components/ContextualInfo'
 import OversizedPanel from '../../components/OversizedPanel'
 import ArrowDownBlue from '../../assets/images/arrow-down-blue.svg'
 import ArrowDownGrey from '../../assets/images/arrow-down-grey.svg'
-import { useExchangeContract, useBlockEffect } from '../../hooks'
-import { useAddressBalance } from '../../contexts/Block'
-import { useTokenDetails } from '../../contexts/Static'
+import { useExchangeContract } from '../../hooks'
+import { useTransactionAdder } from '../../contexts/Transactions'
+import { useTokenDetails } from '../../contexts/Tokens'
+import { useAddressBalance } from '../../contexts/Balances'
 import { calculateGasMargin, amountFormatter } from '../../utils'
-import { useTransactionContext } from '../../contexts/Transaction'
 
 // denominated in bips
 const ALLOWED_SLIPPAGE = ethers.utils.bigNumberify(200)
@@ -71,10 +71,10 @@ function calculateSlippageBounds(value) {
 }
 
 export default function RemoveLiquidity() {
-  const { account, active } = useWeb3Context()
+  const { library, account, active } = useWeb3Context()
   const { t } = useTranslation()
 
-  const { addTransaction } = useTransactionContext()
+  const addTransaction = useTransactionAdder()
 
   const [outputCurrency, setOutputCurrency] = useState('')
   const [value, setValue] = useState('')
@@ -162,8 +162,12 @@ export default function RemoveLiquidity() {
   }, [exchange])
   useEffect(() => {
     fetchPoolTokens()
-  }, [fetchPoolTokens])
-  useBlockEffect(fetchPoolTokens)
+    library.on('block', fetchPoolTokens)
+
+    return () => {
+      library.removeListener('block', fetchPoolTokens)
+    }
+  }, [fetchPoolTokens, library])
 
   async function onRemoveLiquidity() {
     ReactGA.event({
@@ -185,7 +189,7 @@ export default function RemoveLiquidity() {
         gasLimit: calculateGasMargin(estimatedGasLimit, GAS_MARGIN)
       })
       .then(response => {
-        addTransaction(response.hash, response)
+        addTransaction(response)
       })
   }
 

src/pages/Send/index.js

@@ -10,14 +10,14 @@ import OversizedPanel from '../../components/OversizedPanel'
 import AddressInputPanel from '../../components/AddressInputPanel'
 import ArrowDownBlue from '../../assets/images/arrow-down-blue.svg'
 import ArrowDownGrey from '../../assets/images/arrow-down-grey.svg'
-import { useAddressBalance, useAddressAllowance, useExchangeReserves } from '../../contexts/Block'
-import { useTokenDetails } from '../../contexts/Static'
-import { useTransactionContext } from '../../contexts/Transaction'
-import { amountFormatter, calculateGasMargin } from '../../utils'
+import { isAddress, amountFormatter, calculateGasMargin } from '../../utils'
 import { useExchangeContract } from '../../hooks'
+import { useTokenDetails } from '../../contexts/Tokens'
+import { useTransactionAdder } from '../../contexts/Transactions'
+import { useAddressBalance, useExchangeReserves } from '../../contexts/Balances'
+import { useAddressAllowance } from '../../contexts/Allowances'
 
 import './send.scss'
-import { isAddress } from 'web3-utils'
 
 const INPUT = 0
 const OUTPUT = 1
@@ -194,7 +194,7 @@ export default function Swap() {
   const { t } = useTranslation()
   const { account } = useWeb3Context()
 
-  const { addTransaction } = useTransactionContext()
+  const addTransaction = useTransactionAdder()
 
   // analytics
   useEffect(() => {
@@ -619,7 +619,7 @@ export default function Swap() {
 
     const estimatedGasLimit = await estimate(...args, { value })
     method(...args, { value, gasLimit: calculateGasMargin(estimatedGasLimit, GAS_MARGIN) }).then(response => {
-      addTransaction(response.hash, response)
+      addTransaction(response)
     })
   }
 

src/pages/Swap/index.js

@@ -9,11 +9,12 @@ import ContextualInfo from '../../components/ContextualInfo'
 import OversizedPanel from '../../components/OversizedPanel'
 import ArrowDownBlue from '../../assets/images/arrow-down-blue.svg'
 import ArrowDownGrey from '../../assets/images/arrow-down-grey.svg'
-import { useAddressBalance, useAddressAllowance, useExchangeReserves } from '../../contexts/Block'
-import { useTokenDetails } from '../../contexts/Static'
-import { useTransactionContext } from '../../contexts/Transaction'
 import { amountFormatter, calculateGasMargin } from '../../utils'
 import { useExchangeContract } from '../../hooks'
+import { useTokenDetails } from '../../contexts/Tokens'
+import { useTransactionAdder } from '../../contexts/Transactions'
+import { useAddressBalance, useExchangeReserves } from '../../contexts/Balances'
+import { useAddressAllowance } from '../../contexts/Allowances'
 
 import './swap.scss'
 
@@ -192,7 +193,7 @@ export default function Swap() {
   const { t } = useTranslation()
   const { account } = useWeb3Context()
 
-  const { addTransaction } = useTransactionContext()
+  const addTransaction = useTransactionAdder()
 
   // analytics
   useEffect(() => {
@@ -284,7 +285,6 @@ export default function Swap() {
   const [showUnlock, setShowUnlock] = useState(false)
   useEffect(() => {
     const inputValueCalculation = independentField === INPUT ? independentValueParsed : dependentValueMaximum
-
     if (inputBalance && (inputAllowance || inputCurrency === 'ETH') && inputValueCalculation) {
       if (inputBalance.lt(inputValueCalculation)) {
         setInputError(t('insufficientBalance'))
@@ -381,7 +381,6 @@ export default function Swap() {
             if (intermediateValue.lte(ethers.constants.Zero)) {
               throw Error()
             }
-            // console.log('hi!', amountFormatter(intermediateValue, ))
             const calculatedDependentValue = calculateEtherTokenInputFromOutput(
               intermediateValue,
               reserveTokenFirst,
@@ -596,7 +595,7 @@ export default function Swap() {
 
     const estimatedGasLimit = await estimate(...args, { value })
     method(...args, { value, gasLimit: calculateGasMargin(estimatedGasLimit, GAS_MARGIN) }).then(response => {
-      addTransaction(response.hash, response)
+      addTransaction(response)
     })
   }
 

src/theme/index.js

+import React from 'react'
+import { ThemeProvider as StyledComponentsThemeProvider, createGlobalStyle } from 'styled-components'
+
+const theme = {
+  uniswapPink: '#DC6BE5',
+  royalBlue: '#2f80ed',
+  white: '#FFF',
+  black: '#000'
+}
+
+export default function ThemeProvider({ children }) {
+  return <StyledComponentsThemeProvider theme={theme}>{children}</StyledComponentsThemeProvider>
+}
+
+export const GlobalStyle = createGlobalStyle`
+  @import url('https://rsms.me/inter/inter.css');
+  
+  html,
+  body {
+    padding: 0;
+    margin: 0;
+    font-family: Inter, sans-serif;
+    font-variant: none;
+    font-size: 16px;
+    -webkit-font-smoothing: antialiased;
+    -moz-osx-font-smoothing: grayscale;
+    overflow-x: hidden;
+  }
+
+  #root {
+    position: relative;
+    display: flex;
+    flex-flow: column nowrap;
+    height: 100vh;
+    width: 100vw;
+    overflow-x: hidden;
+    overflow-y: auto;
+    background-color: ${props => props.theme.white};
+    z-index: 100;
+    -webkit-tap-highlight-color: rgba(255, 255, 255, 0);
+    @media only screen and (min-width: 768px) {
+      justify-content: center;
+      align-items: center;
+    }
+  }
+
+  #modal-root {
+    position: fixed;
+    top: 0;
+    left: 0;
+    right: 0;
+    z-index: 200;
+  }
+
+  .loader {
+    border: 1px solid transparent;
+    border-top: 1px solid ${props => props.theme.royalBlue};
+    border-radius: 50%;
+    width: 0.75rem;
+    height: 0.75rem;
+    margin-right: 0.25rem;
+    animation: spin 1s cubic-bezier(0.25, 0.46, 0.45, 0.94) infinite;
+  }
+
+  @keyframes spin {
+    0% {
+      transform: rotate(0deg);
+    }
+    100% {
+      transform: rotate(360deg);
+    }
+  }
+`

src/utils/index.js

@@ -14,6 +14,13 @@ export const ERROR_CODES = ['TOKEN_NAME', 'TOKEN_SYMBOL', 'TOKEN_DECIMALS'].redu
   {}
 )
 
+export function safeAccess(object, path) {
+  return path.reduce(
+    (accumulator, currentValue) => (accumulator && accumulator[currentValue] ? accumulator[currentValue] : null),
+    object
+  )
+}
+
 export function isAddress(value) {
   try {
     ethers.utils.getAddress(value)