metamask-extension/ui/app/hooks/useSwappedTokenValue.js

import { TRANSACTION_CATEGORIES } from '../../../shared/constants/transaction';
import { ETH_SWAPS_TOKEN_OBJECT } from '../helpers/constants/swaps';
import { getSwapsTokensReceivedFromTxMeta } from '../pages/swaps/swaps.util';
import { useTokenFiatAmount } from './useTokenFiatAmount';

/**
 * @typedef {Object} SwappedTokenValue
 * @property {string} swapTokenValue - a primary currency string formatted for display
 * @property {string} swapTokenFiatAmount - a secondary currency string formatted for display
 * @property {boolean} isViewingReceivedTokenFromSwap - true if user is on the asset page for the
 *                                                      destination/received asset in a swap.
 */

/**
 * A Swap transaction group's primaryTransaction contains details of the swap,
 * including the source (from) and destination (to) token type (ETH, DAI, etc..)
 * When viewing a non ETH asset page, we need to determine if that asset is the
 * token that was received (destination) from the swap. In that circumstance we
 * would want to show the primaryCurrency in the activity list that is most relevant
 * for that token (- 1000 DAI, for example, when swapping DAI for ETH).
 * @param {import('../selectors').transactionGroup} transactionGroup - Group of transactions by nonce
 * @param {import('./useTokenDisplayValue').Token} currentAsset - The current asset the user is looking at
 * @returns {SwappedTokenValue}
 */
export function useSwappedTokenValue(transactionGroup, currentAsset) {
  const { symbol, decimals, address } = currentAsset;
  const { primaryTransaction, initialTransaction } = transactionGroup;
  const { transactionCategory } = initialTransaction;
  const { from: senderAddress } = initialTransaction.txParams || {};

  const isViewingReceivedTokenFromSwap =
    currentAsset?.symbol === primaryTransaction.destinationTokenSymbol ||
    (currentAsset.address === ETH_SWAPS_TOKEN_OBJECT.address &&
      primaryTransaction.destinationTokenSymbol === 'ETH');

  const swapTokenValue =
    transactionCategory === TRANSACTION_CATEGORIES.SWAP &&
    isViewingReceivedTokenFromSwap
      ? getSwapsTokensReceivedFromTxMeta(
          primaryTransaction.destinationTokenSymbol,
          initialTransaction,
          address,
          senderAddress,
          decimals,
        )
      : transactionCategory === TRANSACTION_CATEGORIES.SWAP &&
        primaryTransaction.swapTokenValue;

  const isNegative =
    typeof swapTokenValue === 'string'
      ? Math.sign(swapTokenValue) === -1
      : false;

  const _swapTokenFiatAmount = useTokenFiatAmount(
    address,
    swapTokenValue || '',
    symbol,
  );
  const swapTokenFiatAmount =
    swapTokenValue && isViewingReceivedTokenFromSwap && _swapTokenFiatAmount;
  return {
    swapTokenValue,
    swapTokenFiatAmount,
    isViewingReceivedTokenFromSwap,
    isNegative,
  };
}