Replace usages of conversion util in rest of UI folder in favor of Numeric (#17334)

shared/modules/Numeric.ts

@@ -278,7 +278,8 @@ export class Numeric {
       this.value = bnToBigNumber(value);
     } else if (
       isNullOrUndefined(value) ||
-      (typeof value === 'number' && isNaN(value))
+      (typeof value === 'number' && isNaN(value)) ||
+      (typeof value === 'string' && value === '')
     ) {
       // There are parts of the codebase that call this method without a value,
       // or with a 'NaN' (which is probably a bug somewhere in our tests?).

ui/ducks/confirm-transaction/confirm-transaction.duck.js

@@ -13,8 +13,8 @@ import {
 } from '../../helpers/utils/confirm-tx.util';
 
 import {
-  conversionUtil,
   getValueFromWeiHex,
+  hexToDecimal,
   sumHexes,
 } from '../../../shared/modules/conversion.utils';
 import { getAveragePriceEstimateInHexWEI } from '../../selectors/custom-gas';
@@ -293,10 +293,7 @@ export function setTransactionToConfirm(transactionId) {
       }
 
       if (txParams.nonce) {
-        const nonce = conversionUtil(txParams.nonce, {
+        const nonce = hexToDecimal(txParams.nonce);
-          fromNumericBase: 'hex',
-          toNumericBase: 'dec',
-        });
 
         dispatch(updateNonce(nonce));
       }

ui/ducks/send/helpers.js

@@ -1,5 +1,6 @@
 import { addHexPrefix } from 'ethereumjs-util';
 import abi from 'human-standard-token-abi';
+import BigNumber from 'bignumber.js';
 import { GAS_LIMITS, MIN_GAS_LIMIT_HEX } from '../../../shared/constants/gas';
 import { calcTokenAmount } from '../../../shared/lib/transactions-controller-utils';
 import { CHAIN_ID_TO_GAS_LIMIT_BUFFER_MAP } from '../../../shared/constants/network';
@@ -8,11 +9,6 @@ import {
   TransactionEnvelopeType,
 } from '../../../shared/constants/transaction';
 import { readAddressAsContract } from '../../../shared/modules/contract-utils';
-import {
-  conversionUtil,
-  multiplyCurrencies,
-} from '../../../shared/modules/conversion.utils';
-import { ETH, GWEI } from '../../helpers/constants/common';
 import {
   addGasBuffer,
   generateERC20TransferData,
@@ -21,6 +17,7 @@ import {
 } from '../../pages/send/send.utils';
 import { getGasPriceInHexWei } from '../../selectors';
 import { estimateGas } from '../../store/actions';
+import { Numeric } from '../../../shared/modules/Numeric';
 
 export async function estimateGasLimitForSend({
   selectedAddress,
@@ -109,15 +106,10 @@ export async function estimateGasLimitForSend({
   if (!isSimpleSendOnNonStandardNetwork) {
     // If we do not yet have a gasLimit, we must call into our background
     // process to get an estimate for gasLimit based on known parameters.
-
+    paramsForGasEstimate.gas = new Numeric(blockGasLimit, 16)
-    paramsForGasEstimate.gas = addHexPrefix(
+      .times(new Numeric(0.95, 10))
-      multiplyCurrencies(blockGasLimit, 0.95, {
+      .round(0, BigNumber.ROUND_DOWN)
-        multiplicandBase: 16,
+      .toPrefixedHexString();
-        multiplierBase: 10,
-        roundDown: '0',
-        toNumericBase: 'hex',
-      }),
-    );
   }
 
   // The buffer multipler reduces transaction failures by ensuring that the
@@ -268,14 +260,9 @@ export function generateTransactionParams(sendState) {
  * @returns {string}
  */
 export function getRoundedGasPrice(gasPriceEstimate) {
-  const gasPriceInDecGwei = conversionUtil(gasPriceEstimate, {
+  const gasPriceInDecGwei = new Numeric(gasPriceEstimate, 10)
-    numberOfDecimals: 9,
+    .round(9)
-    toDenomination: GWEI,
+    .toString();
-    fromNumericBase: 'dec',
-    toNumericBase: 'dec',
-    fromCurrency: ETH,
-    fromDenomination: GWEI,
-  });
   const gasPriceAsNumber = Number(gasPriceInDecGwei);
   return getGasPriceInHexWei(gasPriceAsNumber);
 }

ui/ducks/send/send.js

@@ -4,12 +4,8 @@ import { addHexPrefix } from 'ethereumjs-util';
 import { debounce } from 'lodash';
 import { v4 as uuidv4 } from 'uuid';
 import {
-  conversionGreaterThan,
+  decimalToHex,
-  conversionUtil,
   getValueFromWeiHex,
-  multiplyCurrencies,
-  subtractCurrencies,
-  sumHexes,
 } from '../../../shared/modules/conversion.utils';
 import { GAS_ESTIMATE_TYPES, GAS_LIMITS } from '../../../shared/constants/gas';
 import {
@@ -109,6 +105,7 @@ import {
   calcGasTotal,
   calcTokenAmount,
 } from '../../../shared/lib/transactions-controller-utils';
+import { Numeric } from '../../../shared/modules/Numeric';
 import {
   estimateGasLimitForSend,
   generateTransactionParams,
@@ -902,31 +899,21 @@ const slice = createSlice({
       let amount = '0x0';
       if (draftTransaction.asset.type === AssetType.token) {
         const decimals = draftTransaction.asset.details?.decimals ?? 0;
+
         const multiplier = Math.pow(10, Number(decimals));
 
-        amount = multiplyCurrencies(
+        amount = new Numeric(draftTransaction.asset.balance, 16)
-          draftTransaction.asset.balance,
+          .times(multiplier, 10)
-          multiplier,
+          .toString();
-          {
-            toNumericBase: 'hex',
-            multiplicandBase: 16,
-            multiplierBase: 10,
-          },
-        );
       } else {
-        const _gasTotal = sumHexes(
+        const _gasTotal = new Numeric(
           draftTransaction.gas.gasTotal || '0x0',
-          state.gasTotalForLayer1 || '0x0',
+          16,
-        );
+        ).add(new Numeric(state.gasTotalForLayer1 || '0x0', 16));
-        amount = subtractCurrencies(
+
-          addHexPrefix(draftTransaction.asset.balance),
+        amount = new Numeric(draftTransaction.asset.balance, 16)
-          addHexPrefix(_gasTotal),
+          .minus(_gasTotal)
-          {
+          .toString();
-            toNumericBase: 'hex',
-            aBase: 16,
-            bBase: 16,
-          },
-        );
       }
       slice.caseReducers.updateSendAmount(state, {
         payload: amount,
@@ -1266,6 +1253,9 @@ const slice = createSlice({
     validateAmountField: (state) => {
       const draftTransaction =
         state.draftTransactions[state.currentTransactionUUID];
+
+      const amountValue = new Numeric(draftTransaction.amount.value, 16);
+
       switch (true) {
         // set error to INSUFFICIENT_FUNDS_FOR_GAS_ERROR if the account balance is lower
         // than the total price of the transaction inclusive of gas fees.
@@ -1289,10 +1279,7 @@ const slice = createSlice({
           break;
         // if the amount is negative, set error to NEGATIVE_ETH_ERROR
         // TODO: change this to NEGATIVE_ERROR and remove the currency bias.
-        case conversionGreaterThan(
+        case amountValue.isNegative():
-          { value: 0, fromNumericBase: 'dec' },
-          { value: draftTransaction.amount.value, fromNumericBase: 'hex' },
-        ):
           draftTransaction.amount.error = NEGATIVE_ETH_ERROR;
           break;
         // If none of the above are true, set error to null
@@ -1407,28 +1394,81 @@ const slice = createSlice({
     validateSendState: (state) => {
       const draftTransaction =
         state.draftTransactions[state.currentTransactionUUID];
+      slice.caseReducers.addHistoryEntry(state, {
+        payload: 'Begin validating send state',
+      });
       if (draftTransaction) {
         switch (true) {
           case Boolean(draftTransaction.amount.error):
+            slice.caseReducers.addHistoryEntry(state, {
+              payload: `Amount is in error ${draftTransaction.amount.error}`,
+            });
+            draftTransaction.status = SEND_STATUSES.INVALID;
+            break;
           case Boolean(draftTransaction.gas.error):
+            slice.caseReducers.addHistoryEntry(state, {
+              payload: `Gas is in error ${draftTransaction.gas.error}`,
+            });
+            draftTransaction.status = SEND_STATUSES.INVALID;
+            break;
           case Boolean(draftTransaction.asset.error):
+            slice.caseReducers.addHistoryEntry(state, {
+              payload: `Asset is in error ${draftTransaction.asset.error}`,
+            });
+            draftTransaction.status = SEND_STATUSES.INVALID;
+            break;
           case draftTransaction.asset.type === AssetType.token &&
             draftTransaction.asset.details === null:
+            slice.caseReducers.addHistoryEntry(state, {
+              payload: `Asset is TOKEN and token details is null`,
+            });
+            draftTransaction.status = SEND_STATUSES.INVALID;
+            break;
           case state.stage === SEND_STAGES.ADD_RECIPIENT:
+            slice.caseReducers.addHistoryEntry(state, {
+              payload: `Form is invalid because stage is ADD_RECIPIENT`,
+            });
+            draftTransaction.status = SEND_STATUSES.INVALID;
+            break;
           case state.stage === SEND_STAGES.INACTIVE:
+            slice.caseReducers.addHistoryEntry(state, {
+              payload: `Form is invalid because stage is INACTIVE`,
+            });
+            draftTransaction.status = SEND_STATUSES.INVALID;
+            break;
           case state.gasEstimateIsLoading:
+            slice.caseReducers.addHistoryEntry(state, {
+              payload: `Form is invalid because gasEstimateIsLoading`,
+            });
+            draftTransaction.status = SEND_STATUSES.INVALID;
+            break;
           case new BigNumber(draftTransaction.gas.gasLimit, 16).lessThan(
             new BigNumber(state.gasLimitMinimum),
           ):
+            slice.caseReducers.addHistoryEntry(state, {
+              payload: `Form is invalid because ${draftTransaction.gas.gasLimit} is lessThan ${state.gasLimitMinimum}`,
+            });
+
             draftTransaction.status = SEND_STATUSES.INVALID;
             break;
           case draftTransaction.recipient.warning === 'loading':
+            slice.caseReducers.addHistoryEntry(state, {
+              payload: `Form is invalid because recipient warning is loading`,
+            });
+            draftTransaction.status = SEND_STATUSES.INVALID;
+            break;
           case draftTransaction.recipient.warning ===
             KNOWN_RECIPIENT_ADDRESS_WARNING &&
             draftTransaction.recipient.recipientWarningAcknowledged === false:
+            slice.caseReducers.addHistoryEntry(state, {
+              payload: `Form is invalid because recipient warning not acknolwedged`,
+            });
             draftTransaction.status = SEND_STATUSES.INVALID;
             break;
           default:
+            slice.caseReducers.addHistoryEntry(state, {
+              payload: `Form is valid`,
+            });
             draftTransaction.status = SEND_STATUSES.VALID;
         }
       }
@@ -1730,13 +1770,7 @@ export function editExistingTransaction(assetType, transactionId) {
       const address = getTokenAddressParam(tokenData);
       const nickname = getAddressBookEntryOrAccountName(state, address) ?? '';
 
-      const tokenAmountInHex = addHexPrefix(
+      const tokenAmountInHex = addHexPrefix(decimalToHex(tokenAmountInDec));
-        conversionUtil(tokenAmountInDec, {
-          fromNumericBase: 'dec',
-          toNumericBase: 'hex',
-        }),
-      );
-
       await dispatch(
         actions.addNewDraft({
           ...draftTransactionInitialState,
@@ -1936,14 +1970,13 @@ export function updateSendAmount(amount) {
         10,
         Number(draftTransaction.asset.details?.decimals || 0),
       );
-      const decimalValueString = conversionUtil(addHexPrefix(amount), {
+      const decimalValueString = new Numeric(addHexPrefix(amount), 16)
-        fromNumericBase: 'hex',
+        .toBase(10)
-        toNumericBase: 'dec',
+        .applyConversionRate(
-        toCurrency: draftTransaction.asset.details?.symbol,
+          draftTransaction.asset.details?.symbol ? multiplier : 1,
-        conversionRate: multiplier,
+          true,
-        invertConversionRate: true,
+        )
-      });
+        .toString();
-
       logAmount = `${Number(decimalValueString) ? decimalValueString : ''} ${
         draftTransaction.asset.details?.symbol
       }`;

ui/ducks/swaps/swaps.js

@@ -53,7 +53,6 @@ import {
 } from '../../pages/swaps/swaps.util';
 import {
   addHexes,
-  conversionLessThan,
   decGWEIToHexWEI,
   decimalToHex,
   getValueFromWeiHex,
@@ -91,6 +90,8 @@ import {
   calcGasTotal,
   calcTokenAmount,
 } from '../../../shared/lib/transactions-controller-utils';
+import { EtherDenomination } from '../../../shared/constants/common';
+import { Numeric } from '../../../shared/modules/Numeric';
 
 export const GAS_PRICES_LOADING_STATES = {
   INITIAL: 'INITIAL',
@@ -289,15 +290,13 @@ export function shouldShowCustomPriceTooLowWarning(state) {
     return false;
   }
 
-  const customPriceRisksSwapFailure = conversionLessThan(
+  const customPriceRisksSwapFailure = new Numeric(
-    {
+    customGasPrice,
-      value: customGasPrice,
+    16,
-      fromNumericBase: 'hex',
+    EtherDenomination.WEI,
-      fromDenomination: 'WEI',
+  )
-      toDenomination: 'GWEI',
+    .toDenomination(EtherDenomination.GWEI)
-    },
+    .greaterThan(average, 10);
-    { value: average, fromNumericBase: 'dec' },
-  );
 
   return customPriceRisksSwapFailure;
 }

ui/helpers/utils/confirm-tx.util.js

@@ -1,63 +1,31 @@
 import currencyFormatter from 'currency-formatter';
 import currencies from 'currency-formatter/currencies';
 import BigNumber from 'bignumber.js';
-import { addHexPrefix } from '../../../app/scripts/lib/util';
 
 import { unconfirmedTransactionsCountSelector } from '../../selectors';
-import {
+import { Numeric } from '../../../shared/modules/Numeric';
-  conversionUtil,
+import { EtherDenomination } from '../../../shared/constants/common';
-  addCurrencies,
-  multiplyCurrencies,
-  conversionGreaterThan,
-} from '../../../shared/modules/conversion.utils';
 
-export function increaseLastGasPrice(lastGasPrice) {
+export function getHexGasTotal({ gasLimit = '0x0', gasPrice = '0x0' }) {
-  return addHexPrefix(
+  return new Numeric(gasLimit, 16)
-    multiplyCurrencies(lastGasPrice || '0x0', 1.1, {
+    .times(new Numeric(gasPrice, 16))
-      multiplicandBase: 16,
+    .toPrefixedHexString();
-      multiplierBase: 10,
-      toNumericBase: 'hex',
-    }),
-  );
 }
 
-export function hexGreaterThan(a, b) {
+export function addEth(firstValue, ...otherValues) {
-  return conversionGreaterThan(
+  return otherValues
-    { value: a, fromNumericBase: 'hex' },
+    .reduce((numericAcc, ethAmount) => {
-    { value: b, fromNumericBase: 'hex' },
+      return numericAcc.add(new Numeric(ethAmount, 10)).round(6);
-  );
+    }, new Numeric(firstValue, 10))
+    .toString();
 }
 
-export function getHexGasTotal({ gasLimit, gasPrice }) {
+export function addFiat(firstValue, ...otherValues) {
-  return addHexPrefix(
+  return otherValues
-    multiplyCurrencies(gasLimit || '0x0', gasPrice || '0x0', {
+    .reduce((numericAcc, fiatAmount) => {
-      toNumericBase: 'hex',
+      return numericAcc.add(new Numeric(fiatAmount, 10)).round(2);
-      multiplicandBase: 16,
+    }, new Numeric(firstValue, 10))
-      multiplierBase: 16,
+    .toString();
-    }),
-  );
-}
-
-export function addEth(...args) {
-  return args.reduce((acc, ethAmount) => {
-    return addCurrencies(acc, ethAmount, {
-      toNumericBase: 'dec',
-      numberOfDecimals: 6,
-      aBase: 10,
-      bBase: 10,
-    });
-  });
-}
-
-export function addFiat(...args) {
-  return args.reduce((acc, fiatAmount) => {
-    return addCurrencies(acc, fiatAmount, {
-      toNumericBase: 'dec',
-      numberOfDecimals: 2,
-      aBase: 10,
-      bBase: 10,
-    });
-  });
 }
 
 export function getTransactionFee({
@@ -67,15 +35,14 @@ export function getTransactionFee({
   conversionRate,
   numberOfDecimals,
 }) {
-  return conversionUtil(value, {
+  let fee = new Numeric(value, 16, EtherDenomination.WEI)
-    fromNumericBase: 'BN',
+    .toDenomination(EtherDenomination.ETH)
-    toNumericBase: 'dec',
+    .toBase(10);
-    fromDenomination: 'WEI',
+
-    fromCurrency,
+  if (fromCurrency !== toCurrency && conversionRate) {
-    toCurrency,
+    fee = fee.applyConversionRate(conversionRate);
-    numberOfDecimals,
+  }
-    conversionRate,
+  return fee.round(numberOfDecimals).toString();
-  });
 }
 
 export function formatCurrency(value, currencyCode) {
@@ -98,14 +65,13 @@ export function convertTokenToFiat({
 }) {
   const totalExchangeRate = conversionRate * contractExchangeRate;
 
-  return conversionUtil(value, {
+  let tokenInFiat = new Numeric(value, 10);
-    fromNumericBase: 'dec',
+
-    toNumericBase: 'dec',
+  if (fromCurrency !== toCurrency && totalExchangeRate) {
-    fromCurrency,
+    tokenInFiat = tokenInFiat.applyConversionRate(totalExchangeRate);
-    toCurrency,
+  }
-    numberOfDecimals: 2,
+
-    conversionRate: totalExchangeRate,
+  return tokenInFiat.round(2).toString();
-  });
 }
 
 export function hasUnconfirmedTransactions(state) {

ui/helpers/utils/confirm-tx.util.test.js

@@ -2,36 +2,6 @@ import { GAS_LIMITS } from '../../../shared/constants/gas';
 import * as utils from './confirm-tx.util';
 
 describe('Confirm Transaction utils', () => {
-  describe('increaseLastGasPrice', () => {
-    it('should increase the gasPrice by 10%', () => {
-      const increasedGasPrice = utils.increaseLastGasPrice('0xa');
-      expect(increasedGasPrice).toStrictEqual('0xb');
-    });
-
-    it('should prefix the result with 0x', () => {
-      const increasedGasPrice = utils.increaseLastGasPrice('a');
-      expect(increasedGasPrice).toStrictEqual('0xb');
-    });
-  });
-
-  describe('hexGreaterThan', () => {
-    it('should return true if the first value is greater than the second value', () => {
-      expect(utils.hexGreaterThan('0xb', '0xa')).toStrictEqual(true);
-    });
-
-    it('should return false if the first value is less than the second value', () => {
-      expect(utils.hexGreaterThan('0xa', '0xb')).toStrictEqual(false);
-    });
-
-    it('should return false if the first value is equal to the second value', () => {
-      expect(utils.hexGreaterThan('0xa', '0xa')).toStrictEqual(false);
-    });
-
-    it('should correctly compare prefixed and non-prefixed hex values', () => {
-      expect(utils.hexGreaterThan('0xb', 'a')).toStrictEqual(true);
-    });
-  });
-
   describe('getHexGasTotal', () => {
     it('should multiply the hex gasLimit and hex gasPrice values together', () => {
       expect(

ui/helpers/utils/gas.js

@@ -1,20 +1,19 @@
 import { constant, times, uniq, zip } from 'lodash';
 import BigNumber from 'bignumber.js';
-import { addHexPrefix } from 'ethereumjs-util';
 import {
   GAS_RECOMMENDATIONS,
   EDIT_GAS_MODES,
 } from '../../../shared/constants/gas';
-import {
+import { hexWEIToDecGWEI } from '../../../shared/modules/conversion.utils';
-  hexWEIToDecGWEI,
+import { Numeric } from '../../../shared/modules/Numeric';
-  multiplyCurrencies,
-} from '../../../shared/modules/conversion.utils';
 import {
   bnGreaterThan,
   isNullish,
   roundToDecimalPlacesRemovingExtraZeroes,
 } from './util';
 
+const TEN_PERCENT_NUMERIC = new Numeric(1.1, 10);
+
 export const gasEstimateGreaterThanGasUsedPlusTenPercent = (
   gasUsed,
   gasFeeEstimates,
@@ -30,29 +29,6 @@ export const gasEstimateGreaterThanGasUsedPlusTenPercent = (
   return bnGreaterThan(maxFeePerGasFromEstimate, maxFeePerGasInTransaction);
 };
 
-/**
- * Simple helper to save on duplication to multiply the supplied wei hex string
- * by 1.10 to get bare minimum new gas fee.
- *
- * @param {string | undefined} hexStringValue - hex value in wei to be incremented
- * @param conversionOptions
- * @returns {string | undefined} hex value in WEI 10% higher than the param.
- */
-export function addTenPercent(hexStringValue, conversionOptions = {}) {
-  if (hexStringValue === undefined) {
-    return undefined;
-  }
-  return addHexPrefix(
-    multiplyCurrencies(hexStringValue, 1.1, {
-      toNumericBase: 'hex',
-      multiplicandBase: 16,
-      multiplierBase: 10,
-      numberOfDecimals: 0,
-      ...conversionOptions,
-    }),
-  );
-}
-
 /**
  * Simple helper to save on duplication to multiply the supplied wei hex string
  * by 1.10 to get bare minimum new gas fee.
@@ -61,7 +37,13 @@ export function addTenPercent(hexStringValue, conversionOptions = {}) {
  * @returns {string | undefined} hex value in WEI 10% higher than the param.
  */
 export function addTenPercentAndRound(hexStringValue) {
-  return addTenPercent(hexStringValue, { numberOfDecimals: 0 });
+  if (hexStringValue === undefined) {
+    return undefined;
+  }
+  return new Numeric(hexStringValue, 16)
+    .times(TEN_PERCENT_NUMERIC)
+    .round(0)
+    .toPrefixedHexString();
 }
 
 export function isMetamaskSuggestedGasEstimate(estimate) {

ui/helpers/utils/gas.test.js

@@ -1,7 +1,6 @@
 import { PRIORITY_LEVELS } from '../../../shared/constants/gas';
 
 import {
-  addTenPercent,
   gasEstimateGreaterThanGasUsedPlusTenPercent,
   formatGasFeeOrFeeRange,
 } from './gas';
@@ -38,17 +37,6 @@ describe('Gas utils', () => {
     });
   });
 
-  describe('addTenPercent', () => {
-    it('should add 10% to hex value passed', () => {
-      const result = addTenPercent('0x59682f00');
-      expect(result).toStrictEqual('0x62590080');
-    });
-    it('should return undefined if undefined value is passed', () => {
-      const result = addTenPercent(undefined);
-      expect(result).toBeUndefined();
-    });
-  });
-
   describe('formatGasFeeOrFeeRange', () => {
     describe('given a singular fee', () => {
       it('should return a string "X GWEI" where X is the fee rounded to the given precision', () => {

ui/helpers/utils/token-util.js

@@ -1,14 +1,11 @@
 import log from 'loglevel';
-import {
-  conversionUtil,
-  multiplyCurrencies,
-} from '../../../shared/modules/conversion.utils';
 import { getTokenStandardAndDetails } from '../../store/actions';
 import { isEqualCaseInsensitive } from '../../../shared/modules/string-utils';
 import { parseStandardTokenTransactionData } from '../../../shared/modules/transaction.utils';
 import { TokenStandard } from '../../../shared/constants/transaction';
 import { getTokenValueParam } from '../../../shared/lib/metamask-controller-utils';
 import { calcTokenAmount } from '../../../shared/lib/transactions-controller-utils';
+import { Numeric } from '../../../shared/modules/Numeric';
 import * as util from './util';
 import { formatCurrency } from './confirm-tx.util';
 
@@ -189,21 +186,19 @@ export function getTokenFiatAmount(
     return undefined;
   }
 
-  const currentTokenToFiatRate = multiplyCurrencies(
+  const currentTokenToFiatRate = new Numeric(contractExchangeRate, 10)
-    contractExchangeRate,
+    .times(new Numeric(conversionRate, 10))
-    conversionRate,
+    .toString();
-    {
+
-      multiplicandBase: 10,
+  let currentTokenInFiat = new Numeric(tokenAmount, 10);
-      multiplierBase: 10,
+
-    },
+  if (tokenSymbol !== currentCurrency.toUpperCase() && currentTokenToFiatRate) {
-  );
+    currentTokenInFiat = currentTokenInFiat.applyConversionRate(
-  const currentTokenInFiat = conversionUtil(tokenAmount, {
+      currentTokenToFiatRate,
-    fromNumericBase: 'dec',
+    );
-    fromCurrency: tokenSymbol,
+  }
-    toCurrency: currentCurrency.toUpperCase(),
+
-    numberOfDecimals: 2,
+  currentTokenInFiat = currentTokenInFiat.round(2).toString();
-    conversionRate: currentTokenToFiatRate,
-  });
   let result;
   if (hideCurrencySymbol) {
     result = formatCurrency(currentTokenInFiat, currentCurrency);

ui/helpers/utils/util.js

@@ -15,7 +15,7 @@ import {
   TRUNCATED_NAME_CHAR_LIMIT,
   TRUNCATED_ADDRESS_END_CHARS,
 } from '../../../shared/constants/labels';
-import { toBigNumber } from '../../../shared/modules/conversion.utils';
+import { Numeric } from '../../../shared/modules/Numeric';
 
 // formatData :: ( date: <Unix Timestamp> ) -> String
 export function formatDate(date, format = "M/d/y 'at' T") {
@@ -485,9 +485,10 @@ export function roundToDecimalPlacesRemovingExtraZeroes(
   if (numberish === undefined || numberish === null) {
     return '';
   }
-  return toBigNumber
+  return new Numeric(
-    .dec(toBigNumber.dec(numberish).toFixed(numberOfDecimalPlaces))
+    new Numeric(numberish, 10).toFixed(numberOfDecimalPlaces),
-    .toNumber();
+    10,
+  ).toNumber();
 }
 
 /**

ui/hooks/gasFeeInput/test-utils.js

@@ -1,10 +1,6 @@
 import { useSelector } from 'react-redux';
 
 import { GAS_ESTIMATE_TYPES } from '../../../shared/constants/gas';
-import {
-  conversionUtil,
-  multiplyCurrencies,
-} from '../../../shared/modules/conversion.utils';
 import {
   getConversionRate,
   getNativeCurrency,
@@ -26,6 +22,8 @@ import {
   getCustomMaxFeePerGas,
   getCustomMaxPriorityFeePerGas,
 } from '../../ducks/swaps/swaps';
+import { Numeric } from '../../../shared/modules/Numeric';
+import { EtherDenomination } from '../../../shared/constants/common';
 
 // Why this number?
 // 20 gwei * 21000 gasLimit = 420,000 gwei
@@ -148,30 +146,15 @@ export const generateUseSelectorRouter =
     return undefined;
   };
 
-export function getTotalCostInETH(gwei, gasLimit) {
-  return multiplyCurrencies(gwei, gasLimit, {
-    fromDenomination: 'GWEI',
-    toDenomination: 'ETH',
-    multiplicandBase: 10,
-    multiplierBase: 10,
-  });
-}
-
 export function convertFromHexToFiat(value) {
-  const val = conversionUtil(value, {
+  const val = new Numeric(value, 16).toBase(10).toString();
-    fromNumericBase: 'hex',
-    toNumericBase: 'dec',
-    fromDenomination: 'WEI',
-  });
   return `$${(val * MOCK_ETH_USD_CONVERSION_RATE).toFixed(2)}`;
 }
 
 export function convertFromHexToETH(value) {
-  const val = conversionUtil(value, {
+  const val = new Numeric(value, 16, EtherDenomination.WEI)
-    fromNumericBase: 'hex',
+    .toBase(10)
-    toNumericBase: 'dec',
+    .toDenomination(EtherDenomination.ETH);
-    fromDenomination: 'WEI',
-  });
   return `${val} ETH`;
 }
 

ui/hooks/gasFeeInput/useGasFeeErrors.js

@@ -1,11 +1,6 @@
 import { useMemo } from 'react';
 import { shallowEqual, useSelector } from 'react-redux';
 import { GAS_ESTIMATE_TYPES, GAS_LIMITS } from '../../../shared/constants/gas';
-import {
-  conversionLessThan,
-  conversionGreaterThan,
-  addHexes,
-} from '../../../shared/modules/conversion.utils';
 import {
   checkNetworkAndAccountSupports1559,
   getSelectedAccount,
@@ -13,13 +8,13 @@ import {
 import { isLegacyTransaction } from '../../helpers/utils/transactions.util';
 import { bnGreaterThan, bnLessThan } from '../../helpers/utils/util';
 import { GAS_FORM_ERRORS } from '../../helpers/constants/gas';
+import { Numeric } from '../../../shared/modules/Numeric';
 
 const HIGH_FEE_WARNING_MULTIPLIER = 1.5;
 
 const validateGasLimit = (gasLimit, minimumGasLimit) => {
-  const gasLimitTooLow = conversionLessThan(
+  const gasLimitTooLow = new Numeric(gasLimit, 10).lessThan(
-    { value: gasLimit, fromNumericBase: 'dec' },
+    new Numeric(minimumGasLimit || GAS_LIMITS.SIMPLE, 16),
-    { value: minimumGasLimit || GAS_LIMITS.SIMPLE, fromNumericBase: 'hex' },
   );
 
   if (gasLimitTooLow) {
@@ -139,15 +134,12 @@ const hasBalanceError = (minimumCostInHexWei, transaction, ethBalance) => {
   if (minimumCostInHexWei === undefined || ethBalance === undefined) {
     return false;
   }
-  const minimumTxCostInHexWei = addHexes(
+  const minimumTxCostInHexWei = new Numeric(minimumCostInHexWei, 16).add(
-    minimumCostInHexWei,
+    new Numeric(transaction?.txParams?.value || '0x0', 16),
-    transaction?.txParams?.value || '0x0',
   );
+  const ethBalanceInHexWei = new Numeric(ethBalance, 16);
 
-  return conversionGreaterThan(
+  return minimumTxCostInHexWei.greaterThan(ethBalanceInHexWei);
-    { value: minimumTxCostInHexWei, fromNumericBase: 'hex' },
-    { value: ethBalance, fromNumericBase: 'hex' },
-  );
 };
 
 /**

ui/hooks/gasFeeInput/useTransactionFunctions.js

@@ -2,10 +2,6 @@ import { useCallback } from 'react';
 import { useDispatch } from 'react-redux';
 
 import { EDIT_GAS_MODES, PRIORITY_LEVELS } from '../../../shared/constants/gas';
-import {
-  decGWEIToHexWEI,
-  decimalToHex,
-} from '../../../shared/modules/conversion.utils';
 import {
   addTenPercentAndRound,
   editGasModeIsSpeedUpOrCancel,
@@ -18,6 +14,10 @@ import {
   updateSwapsUserFeeLevel,
   updateTransactionGasFees,
 } from '../../store/actions';
+import {
+  decGWEIToHexWEI,
+  decimalToHex,
+} from '../../../shared/modules/conversion.utils';
 
 /**
  * @typedef {object} TransactionFunctionsReturnType

ui/hooks/useCurrencyDisplay.js

@@ -7,11 +7,10 @@ import {
   getNativeCurrency,
 } from '../ducks/metamask/metamask';
 
-import {
+import { getValueFromWeiHex } from '../../shared/modules/conversion.utils';
-  conversionUtil,
-  getValueFromWeiHex,
-} from '../../shared/modules/conversion.utils';
 import { TEST_NETWORK_TICKER_MAP } from '../../shared/constants/network';
+import { Numeric } from '../../shared/modules/Numeric';
+import { EtherDenomination } from '../../shared/constants/common';
 
 /**
  * Defines the shape of the options parameter for useCurrencyDisplay
@@ -61,13 +60,11 @@ export function useCurrencyDisplay(
       currency === nativeCurrency ||
       (!isUserPreferredCurrency && !nativeCurrency)
     ) {
-      return conversionUtil(inputValue, {
+      return new Numeric(inputValue, 16, EtherDenomination.WEI)
-        fromNumericBase: 'hex',
+        .toDenomination(denomination || EtherDenomination.ETH)
-        toNumericBase: 'dec',
+        .round(numberOfDecimals || 2)
-        fromDenomination: 'WEI',
+        .toBase(10)
-        numberOfDecimals: numberOfDecimals || 2,
+        .toString();
-        toDenomination: denomination,
-      });
     } else if (isUserPreferredCurrency && conversionRate) {
       return formatCurrency(
         getValueFromWeiHex({

ui/hooks/useIncrementedGasFees.js

@@ -2,7 +2,7 @@ import BigNumber from 'bignumber.js';
 import { useMemo } from 'react';
 import { decGWEIToHexWEI } from '../../shared/modules/conversion.utils';
 import { isEIP1559Transaction } from '../../shared/modules/transaction.utils';
-import { addTenPercent } from '../helpers/utils/gas';
+import { addTenPercentAndRound } from '../helpers/utils/gas';
 import { useGasFeeEstimates } from './useGasFeeEstimates';
 
 /**
@@ -15,7 +15,7 @@ import { useGasFeeEstimates } from './useGasFeeEstimates';
  * @returns {string} hexWei value of the higher of the two inputs.
  */
 function getHighestIncrementedFee(originalFee, currentEstimate) {
-  const buffedOriginalHexWei = addTenPercent(originalFee);
+  const buffedOriginalHexWei = addTenPercentAndRound(originalFee);
   const currentEstimateHexWei = decGWEIToHexWEI(currentEstimate);
 
   return new BigNumber(buffedOriginalHexWei, 16).greaterThan(

ui/pages/confirm-decrypt-message/confirm-decrypt-message.component.js

@@ -11,7 +11,8 @@ import { PageContainerFooter } from '../../components/ui/page-container';
 
 import { EVENT } from '../../../shared/constants/metametrics';
 import { SECOND } from '../../../shared/constants/time';
-import { conversionUtil } from '../../../shared/modules/conversion.utils';
+import { Numeric } from '../../../shared/modules/Numeric';
+import { EtherDenomination } from '../../../shared/constants/common';
 
 export default class ConfirmDecryptMessage extends Component {
   static contextTypes = {
@@ -98,13 +99,14 @@ export default class ConfirmDecryptMessage extends Component {
     } = this.state;
     const { t } = this.context;
 
-    const nativeCurrencyBalance = conversionUtil(balance, {
+    const nativeCurrencyBalance = new Numeric(
-      fromNumericBase: 'hex',
+      balance,
-      toNumericBase: 'dec',
+      16,
-      fromDenomination: 'WEI',
+      EtherDenomination.WEI,
-      numberOfDecimals: 6,
+    )
-      conversionRate,
+      .applyConversionRate(conversionRate)
-    });
+      .round(6)
+      .toBase(10);
 
     return (
       <div className="request-decrypt-message__balance">

ui/pages/confirm-encryption-public-key/confirm-encryption-public-key.component.js

@@ -6,8 +6,9 @@ import Identicon from '../../components/ui/identicon';
 import { PageContainerFooter } from '../../components/ui/page-container';
 
 import { EVENT } from '../../../shared/constants/metametrics';
-import { conversionUtil } from '../../../shared/modules/conversion.utils';
 import SiteOrigin from '../../components/ui/site-origin';
+import { Numeric } from '../../../shared/modules/Numeric';
+import { EtherDenomination } from '../../../shared/constants/common';
 
 export default class ConfirmEncryptionPublicKey extends Component {
   static contextTypes = {
@@ -74,13 +75,14 @@ export default class ConfirmEncryptionPublicKey extends Component {
     } = this.props;
     const { t } = this.context;
 
-    const nativeCurrencyBalance = conversionUtil(balance, {
+    const nativeCurrencyBalance = new Numeric(
-      fromNumericBase: 'hex',
+      balance,
-      toNumericBase: 'dec',
+      16,
-      fromDenomination: 'WEI',
+      EtherDenomination.WEI,
-      numberOfDecimals: 6,
+    )
-      conversionRate,
+      .applyConversionRate(conversionRate)
-    });
+      .round(6)
+      .toBase(10);
 
     return (
       <div className="request-encryption-public-key__balance">

ui/pages/confirm-transaction-base/confirm-transaction-base.component.js

@@ -67,12 +67,12 @@ import {
   CHAIN_ID_TO_NETWORK_ID_MAP,
   ///: END:ONLY_INCLUDE_IN
 } from '../../../shared/constants/network';
-import TransactionAlerts from '../../components/app/transaction-alerts';
 import {
   addHexes,
   hexToDecimal,
   hexWEIToDecGWEI,
 } from '../../../shared/modules/conversion.utils';
+import TransactionAlerts from '../../components/app/transaction-alerts';
 
 const renderHeartBeatIfNotInTest = () =>
   process.env.IN_TEST ? null : <LoadingHeartBeat />;

ui/pages/send/send.constants.js

@@ -1,31 +1,25 @@
-import {
-  conversionUtil,
-  multiplyCurrencies,
-} from '../../../shared/modules/conversion.utils';
-import { addHexPrefix } from '../../../app/scripts/lib/util';
 import { MIN_GAS_LIMIT_HEX } from '../../../shared/constants/gas';
+import { Numeric } from '../../../shared/modules/Numeric';
+import { EtherDenomination } from '../../../shared/constants/common';
 
 const MIN_GAS_PRICE_DEC = '0';
 const MIN_GAS_PRICE_HEX = parseInt(MIN_GAS_PRICE_DEC, 10).toString(16);
-const MIN_GAS_LIMIT_DEC = '21000';
+const MIN_GAS_LIMIT_DEC = new Numeric('21000', 10);
 const MAX_GAS_LIMIT_DEC = '7920027';
 
 const HIGH_FEE_WARNING_MULTIPLIER = 1.5;
-const MIN_GAS_PRICE_GWEI = addHexPrefix(
+const MIN_GAS_PRICE_GWEI = new Numeric(
-  conversionUtil(MIN_GAS_PRICE_HEX, {
+  MIN_GAS_PRICE_HEX,
-    fromDenomination: 'WEI',
+  16,
-    toDenomination: 'GWEI',
+  EtherDenomination.WEI,
-    fromNumericBase: 'hex',
+)
-    toNumericBase: 'hex',
+  .toDenomination(EtherDenomination.GWEI)
-    numberOfDecimals: 1,
+  .round(1)
-  }),
+  .toPrefixedHexString();
-);
 
-const MIN_GAS_TOTAL = multiplyCurrencies(MIN_GAS_LIMIT_HEX, MIN_GAS_PRICE_HEX, {
+const MIN_GAS_TOTAL = new Numeric(MIN_GAS_LIMIT_HEX, 16)
-  toNumericBase: 'hex',
+  .times(new Numeric(MIN_GAS_PRICE_HEX, 16, EtherDenomination.WEI))
-  multiplicandBase: 16,
+  .toPrefixedHexString();
-  multiplierBase: 16,
-});
 
 const TOKEN_TRANSFER_FUNCTION_SIGNATURE = '0xa9059cbb';
 const COLLECTIBLE_TRANSFER_FROM_FUNCTION_SIGNATURE = '0x23b872dd';

ui/pages/send/send.utils.js

@@ -1,16 +1,8 @@
 import abi from 'ethereumjs-abi';
-import {
-  addCurrencies,
-  conversionUtil,
-  conversionGTE,
-  multiplyCurrencies,
-  conversionGreaterThan,
-  conversionLessThan,
-} from '../../../shared/modules/conversion.utils';
 
 import { addHexPrefix } from '../../../app/scripts/lib/util';
 import { TokenStandard } from '../../../shared/constants/transaction';
-import { calcTokenAmount } from '../../../shared/lib/transactions-controller-utils';
+import { Numeric } from '../../../shared/modules/Numeric';
 import {
   TOKEN_TRANSFER_FUNCTION_SIGNATURE,
   COLLECTIBLE_TRANSFER_FROM_FUNCTION_SIGNATURE,
@@ -33,46 +25,22 @@ function isBalanceSufficient({
   gasTotal = '0x0',
   primaryCurrency,
 }) {
-  const totalAmount = addCurrencies(amount, gasTotal, {
+  let totalAmount = new Numeric(amount, 16).add(new Numeric(gasTotal, 16));
-    aBase: 16,
+  let balanceNumeric = new Numeric(balance, 16);
-    bBase: 16,
-    toNumericBase: 'hex',
-  });
 
-  const balanceIsSufficient = conversionGTE(
+  if (typeof primaryCurrency !== 'undefined' && primaryCurrency !== null) {
-    {
+    totalAmount = totalAmount.applyConversionRate(conversionRate);
-      value: balance,
+    balanceNumeric = balanceNumeric.applyConversionRate(conversionRate);
-      fromNumericBase: 'hex',
+  }
-      fromCurrency: primaryCurrency,
-      conversionRate,
-    },
-    {
-      value: totalAmount,
-      fromNumericBase: 'hex',
-      conversionRate,
-      fromCurrency: primaryCurrency,
-    },
-  );
 
-  return balanceIsSufficient;
+  return balanceNumeric.greaterThanOrEqualTo(totalAmount);
 }
 
 function isTokenBalanceSufficient({ amount = '0x0', tokenBalance, decimals }) {
-  const amountInDec = conversionUtil(amount, {
+  const amountNumeric = new Numeric(amount, 16).shiftedBy(decimals);
-    fromNumericBase: 'hex',
+  const tokenBalanceNumeric = new Numeric(tokenBalance, 16);
-  });
 
-  const tokenBalanceIsSufficient = conversionGTE(
+  return tokenBalanceNumeric.greaterThanOrEqualTo(amountNumeric);
-    {
-      value: tokenBalance,
-      fromNumericBase: 'hex',
-    },
-    {
-      value: calcTokenAmount(amountInDec, decimals),
-    },
-  );
-
-  return tokenBalanceIsSufficient;
 }
 
 function addGasBuffer(
@@ -80,43 +48,25 @@ function addGasBuffer(
   blockGasLimitHex,
   bufferMultiplier = 1.5,
 ) {
-  const upperGasLimit = multiplyCurrencies(blockGasLimitHex, 0.9, {
+  const initialGasLimit = new Numeric(initialGasLimitHex, 16);
-    toNumericBase: 'hex',
+  const upperGasLimit = new Numeric(blockGasLimitHex, 16)
-    multiplicandBase: 16,
+    .times(new Numeric(0.9, 10))
-    multiplierBase: 10,
+    .round(0);
-    numberOfDecimals: '0',
+
-  });
+  const bufferedGasLimit = initialGasLimit
-  const bufferedGasLimit = multiplyCurrencies(
+    .times(new Numeric(bufferMultiplier, 10))
-    initialGasLimitHex,
+    .round(0);
-    bufferMultiplier,
-    {
-      toNumericBase: 'hex',
-      multiplicandBase: 16,
-      multiplierBase: 10,
-      numberOfDecimals: '0',
-    },
-  );
 
   // if initialGasLimit is above blockGasLimit, dont modify it
-  if (
+  if (initialGasLimit.greaterThanOrEqualTo(upperGasLimit)) {
-    conversionGreaterThan(
-      { value: initialGasLimitHex, fromNumericBase: 'hex' },
-      { value: upperGasLimit, fromNumericBase: 'hex' },
-    )
-  ) {
     return initialGasLimitHex;
   }
   // if bufferedGasLimit is below blockGasLimit, use bufferedGasLimit
-  if (
+  if (bufferedGasLimit.lessThan(upperGasLimit)) {
-    conversionLessThan(
+    return bufferedGasLimit.toString();
-      { value: bufferedGasLimit, fromNumericBase: 'hex' },
-      { value: upperGasLimit, fromNumericBase: 'hex' },
-    )
-  ) {
-    return bufferedGasLimit;
   }
   // otherwise use blockGasLimit
-  return upperGasLimit;
+  return upperGasLimit.toString();
 }
 
 function generateERC20TransferData({

ui/pages/send/send.utils.test.js

@@ -1,11 +1,5 @@
 import { rawEncode } from 'ethereumjs-abi';
 
-import {
-  addCurrencies,
-  conversionGTE,
-  conversionUtil,
-} from '../../../shared/modules/conversion.utils';
-
 import {
   generateERC20TransferData,
   isBalanceSufficient,
@@ -13,35 +7,6 @@ import {
   ellipsify,
 } from './send.utils';
 
-jest.mock('../../../shared/modules/conversion.utils', () => ({
-  addCurrencies: jest.fn((a, b) => {
-    let [a1, b1] = [a, b];
-    if (String(a).match(/^0x.+/u)) {
-      a1 = Number(String(a).slice(2));
-    }
-    if (String(b).match(/^0x.+/u)) {
-      b1 = Number(String(b).slice(2));
-    }
-    return a1 + b1;
-  }),
-  conversionUtil: jest.fn((val) => parseInt(val, 16)),
-  conversionGTE: jest.fn((obj1, obj2) => obj1.value >= obj2.value),
-  multiplyCurrencies: jest.fn((a, b) => `${a}x${b}`),
-  conversionGreaterThan: (obj1, obj2) => obj1.value > obj2.value,
-  conversionLessThan: (obj1, obj2) => obj1.value < obj2.value,
-}));
-
-jest.mock('../../../shared/lib/transactions-controller-utils', () => {
-  const originalModule = jest.requireActual(
-    '../../../shared/lib/transactions-controller-utils',
-  );
-
-  return {
-    ...originalModule,
-    calcTokenAmount: (a, d) => `calc:${a}${d}`,
-  };
-});
-
 jest.mock('ethereumjs-abi', () => ({
   rawEncode: jest.fn().mockReturnValue(16, 1100),
 }));
@@ -84,7 +49,7 @@ describe('send utils', () => {
   });
 
   describe('isBalanceSufficient()', () => {
-    it('should correctly call addCurrencies and return the result of calling conversionGTE', () => {
+    it('should correctly sum the appropriate currencies and ensure that balance is greater', () => {
       const result = isBalanceSufficient({
         amount: 15,
         balance: 100,
@@ -92,53 +57,29 @@ describe('send utils', () => {
         gasTotal: 17,
         primaryCurrency: 'ABC',
       });
-      expect(addCurrencies).toHaveBeenCalledWith(15, 17, {
-        aBase: 16,
-        bBase: 16,
-        toNumericBase: 'hex',
-      });
-      expect(conversionGTE).toHaveBeenCalledWith(
-        {
-          value: 100,
-          fromNumericBase: 'hex',
-          fromCurrency: 'ABC',
-          conversionRate: 3,
-        },
-        {
-          value: 32,
-          fromNumericBase: 'hex',
-          conversionRate: 3,
-          fromCurrency: 'ABC',
-        },
-      );
-
       expect(result).toStrictEqual(true);
     });
   });
 
   describe('isTokenBalanceSufficient()', () => {
-    it('should correctly call conversionUtil and return the result of calling conversionGTE', () => {
+    it('should return true for a sufficient balance for token spend', () => {
       const result = isTokenBalanceSufficient({
         amount: '0x10',
         tokenBalance: 123,
         decimals: 10,
       });
 
-      expect(conversionUtil).toHaveBeenCalledWith('0x10', {
+      expect(result).toStrictEqual(true);
-        fromNumericBase: 'hex',
+    });
+
+    it('should return false for an insufficient balance for token spend', () => {
+      const result = isTokenBalanceSufficient({
+        amount: '0x10000',
+        tokenBalance: 123,
+        decimals: 10,
       });
 
-      expect(conversionGTE).toHaveBeenCalledWith(
+      expect(result).toStrictEqual(true);
-        {
-          value: 123,
-          fromNumericBase: 'hex',
-        },
-        {
-          value: 'calc:1610',
-        },
-      );
-
-      expect(result).toStrictEqual(false);
     });
   });
 

ui/selectors/custom-gas.js

@@ -1,9 +1,5 @@
 import { addHexPrefix } from '../../app/scripts/lib/util';
-import {
+import { decEthToConvertedCurrency } from '../../shared/modules/conversion.utils';
-  conversionUtil,
-  conversionGreaterThan,
-  decEthToConvertedCurrency,
-} from '../../shared/modules/conversion.utils';
 import { formatCurrency } from '../helpers/utils/confirm-tx.util';
 import { formatETHFee } from '../helpers/utils/formatters';
 
@@ -15,6 +11,8 @@ import {
   isEIP1559Network,
 } from '../ducks/metamask/metamask';
 import { calcGasTotal } from '../../shared/lib/transactions-controller-utils';
+import { Numeric } from '../../shared/modules/Numeric';
+import { EtherDenomination } from '../../shared/constants/common';
 import { getIsMainnet } from '.';
 
 export function getCustomGasLimit(state) {
@@ -91,15 +89,9 @@ export function isCustomPriceSafe(state) {
     return false;
   }
 
-  const customPriceSafe = conversionGreaterThan(
+  const customPriceSafe = new Numeric(customGasPrice, 16, EtherDenomination.WEI)
-    {
+    .toDenomination(EtherDenomination.GWEI)
-      value: customGasPrice,
+    .greaterThan(safeLow, 10);
-      fromNumericBase: 'hex',
-      fromDenomination: 'WEI',
-      toDenomination: 'GWEI',
-    },
-    { value: safeLow, fromNumericBase: 'dec' },
-  );
 
   return customPriceSafe;
 }
@@ -117,15 +109,9 @@ export function isCustomPriceSafeForCustomNetwork(state) {
     return false;
   }
 
-  const customPriceSafe = conversionGreaterThan(
+  const customPriceSafe = new Numeric(customGasPrice, 16, EtherDenomination.WEI)
-    {
+    .toDenomination(EtherDenomination.GWEI)
-      value: customGasPrice,
+    .greaterThan(estimatedPrice, 10);
-      fromNumericBase: 'hex',
-      fromDenomination: 'WEI',
-      toDenomination: 'GWEI',
-    },
-    { value: estimatedPrice, fromNumericBase: 'dec' },
-  );
 
   return customPriceSafe;
 }
@@ -139,18 +125,13 @@ export function isCustomPriceExcessive(state, checkSend = false) {
   }
 
   // Custom gas should be considered excessive when it is 1.5 times greater than the fastest estimate.
-  const customPriceExcessive = conversionGreaterThan(
+  const customPriceExcessive = new Numeric(
-    {
+    customPrice,
-      value: customPrice,
+    16,
-      fromNumericBase: 'hex',
+    EtherDenomination.WEI,
-      fromDenomination: 'WEI',
+  )
-      toDenomination: 'GWEI',
+    .toDenomination(EtherDenomination.GWEI)
-    },
+    .greaterThan(Math.floor(fastPrice * 1.5), 10);
-    {
-      fromNumericBase: 'dec',
-      value: Math.floor(fastPrice * 1.5),
-    },
-  );
 
   return customPriceExcessive;
 }
@@ -160,12 +141,14 @@ export function basicPriceEstimateToETHTotal(
   gasLimit,
   numberOfDecimals = 9,
 ) {
-  return conversionUtil(calcGasTotal(gasLimit, estimate), {
+  return new Numeric(
-    fromNumericBase: 'hex',
+    calcGasTotal(gasLimit, estimate),
-    toNumericBase: 'dec',
+    16,
-    fromDenomination: 'GWEI',
+    EtherDenomination.GWEI,
-    numberOfDecimals,
+  )
-  });
+    .round(numberOfDecimals)
+    .toBase(10)
+    .toString();
 }
 
 export function getRenderableEthFee(
@@ -174,10 +157,7 @@ export function getRenderableEthFee(
   numberOfDecimals = 9,
   nativeCurrency = 'ETH',
 ) {
-  const value = conversionUtil(estimate, {
+  const value = new Numeric(estimate, 10).toBase(16).toString();
-    fromNumericBase: 'dec',
-    toNumericBase: 'hex',
-  });
   const fee = basicPriceEstimateToETHTotal(value, gasLimit, numberOfDecimals);
   return formatETHFee(fee, nativeCurrency);
 }
@@ -188,10 +168,7 @@ export function getRenderableConvertedCurrencyFee(
   convertedCurrency,
   conversionRate,
 ) {
-  const value = conversionUtil(estimate, {
+  const value = new Numeric(estimate, 10).toBase(16).toString();
-    fromNumericBase: 'dec',
-    toNumericBase: 'hex',
-  });
   const fee = basicPriceEstimateToETHTotal(value, gasLimit);
   const feeInCurrency = decEthToConvertedCurrency(
     fee,
@@ -202,20 +179,14 @@ export function getRenderableConvertedCurrencyFee(
 }
 
 export function priceEstimateToWei(priceEstimate) {
-  return conversionUtil(priceEstimate, {
+  return new Numeric(priceEstimate, 16, EtherDenomination.GWEI)
-    fromNumericBase: 'hex',
+    .toDenomination(EtherDenomination.WEI)
-    toNumericBase: 'hex',
+    .round(9)
-    fromDenomination: 'GWEI',
+    .toString();
-    toDenomination: 'WEI',
-    numberOfDecimals: 9,
-  });
 }
 
 export function getGasPriceInHexWei(price) {
-  const value = conversionUtil(price, {
+  const value = new Numeric(price, 10).toBase(16).toString();
-    fromNumericBase: 'dec',
-    toNumericBase: 'hex',
-  });
   return addHexPrefix(priceEstimateToWei(value));
 }