mirror of
https://github.com/kremalicious/metamask-extension.git
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50 lines
1.5 KiB
JavaScript
50 lines
1.5 KiB
JavaScript
import { TRANSACTION_TYPES } from '../../../shared/constants/transaction';
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import { decimalToHex } from '../../helpers/utils/conversions.util';
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import {
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calcTokenValue,
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getTokenAddressParam,
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} from '../../helpers/utils/token-util';
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import { getTokenData } from '../../helpers/utils/transactions.util';
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export function getCustomTxParamsData(
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data,
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{ customPermissionAmount, decimals },
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) {
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const tokenData = getTokenData(data);
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if (!tokenData) {
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throw new Error('Invalid data');
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} else if (tokenData.name !== TRANSACTION_TYPES.TOKEN_METHOD_APPROVE) {
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throw new Error(
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`Invalid data; should be 'approve' method, but instead is '${tokenData.name}'`,
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);
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}
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let spender = getTokenAddressParam(tokenData);
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if (spender.startsWith('0x')) {
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spender = spender.substring(2);
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}
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const [signature, tokenValue] = data.split(spender);
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if (!signature || !tokenValue) {
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throw new Error('Invalid data');
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} else if (tokenValue.length !== 64) {
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throw new Error(
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'Invalid token value; should be exactly 64 hex digits long (u256)',
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);
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}
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let customPermissionValue = decimalToHex(
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calcTokenValue(customPermissionAmount, decimals),
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);
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if (customPermissionValue.length > 64) {
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throw new Error('Custom value is larger than u256');
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}
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customPermissionValue = customPermissionValue.padStart(
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tokenValue.length,
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'0',
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);
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const customTxParamsData = `${signature}${spender}${customPermissionValue}`;
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return customTxParamsData;
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}
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