@base-org/account
Version:
Base Account SDK
98 lines • 4.32 kB
JavaScript
import { parseUnits } from 'viem';
import { fetchPermission, prepareSpendCallData, } from '../public-utilities/spend-permission/index.js';
import { TOKENS } from './constants.js';
import { validateUSDCBasePermission } from './utils/validateUSDCBasePermission.js';
/**
* Prepares call data for charging a subscription.
*
* This function fetches the subscription (spend permission) details using its ID (permission hash)
* and prepares the necessary call data to charge the subscription. It wraps the lower-level
* prepareSpendCallData function with subscription-specific logic.
*
* The resulting call data includes:
* - An approval call (if the permission is not yet active)
* - A spend call to charge the subscription
*
* @param options - Options for preparing the charge
* @param options.id - The subscription ID (permission hash) returned from subscribe()
* @param options.amount - Amount to charge as a string (e.g., "10.50") or 'max-remaining-charge'
* @param options.testnet - Whether this permission is on testnet (Base Sepolia). Defaults to false (mainnet)
* @param options.recipient - Optional recipient address to receive the charged USDC
* @param options.rpcUrl - Optional custom RPC URL to use for blockchain queries. Useful for avoiding rate limits on public endpoints.
* @returns Promise<PrepareChargeResult> - Array of call data for the charge
* @throws Error if the subscription cannot be found or if the amount exceeds remaining allowance
*
* @example
* ```typescript
* import { base } from '@base-org/account/payment';
*
* // Prepare to charge a specific amount from a subscription
* const chargeCalls = await base.subscription.prepareCharge({
* id: '0x71319cd488f8e4f24687711ec5c95d9e0c1bacbf5c1064942937eba4c7cf2984',
* amount: '9.99',
* testnet: false
* });
*
* // Prepare to charge the full remaining charge
* const maxChargeCalls = await base.subscription.prepareCharge({
* id: '0x71319cd488f8e4f24687711ec5c95d9e0c1bacbf5c1064942937eba4c7cf2984',
* amount: 'max-remaining-charge'
* });
*
* // Prepare to charge and transfer to a recipient
* const chargeWithRecipient = await base.subscription.prepareCharge({
* id: '0x71319cd488f8e4f24687711ec5c95d9e0c1bacbf5c1064942937eba4c7cf2984',
* amount: '10.00',
* recipient: '0x0000000000000000000000000000000000000001'
* });
*
* // With custom RPC URL to avoid rate limits
* const chargeWithCustomRpc = await base.subscription.prepareCharge({
* id: '0x71319cd488f8e4f24687711ec5c95d9e0c1bacbf5c1064942937eba4c7cf2984',
* amount: '9.99',
* testnet: false,
* rpcUrl: 'https://my-custom-rpc.example.com'
* });
*
* // Send the calls using your app's spender account
* await provider.request({
* method: 'wallet_sendCalls',
* params: [{
* version: '2.0.0',
* atomicRequired: true,
* from: subscriptionOwner, // Must be the spender/subscription owner!
* chainId: testnet ? '0x14a34' : '0x2105',
* calls: chargeCalls,
* }],
* });
* ```
*/
export async function prepareCharge(options) {
const { id, amount, testnet = false, recipient, rpcUrl } = options;
// Fetch the permission using the subscription ID (permission hash)
const permission = await fetchPermission({
permissionHash: id,
});
// If no permission found, throw an error
if (!permission) {
throw new Error(`Subscription with ID ${id} not found`);
}
// Validate this is a USDC permission on the correct network
validateUSDCBasePermission(permission, testnet);
// Determine the amount to pass to prepareSpendCallData
let spendAmount;
if (amount === 'max-remaining-charge') {
// Pass 'max-remaining-allowance' to prepareSpendCallData
// It will handle getting the permission status internally
spendAmount = 'max-remaining-allowance';
}
else {
// Parse the USD amount string to USDC wei (6 decimals)
// For example, "10.50" becomes 10500000n (10.50 * 10^6)
spendAmount = parseUnits(amount, TOKENS.USDC.decimals);
}
// Call the existing prepareSpendCallData utility with the optional recipient and rpcUrl
const callData = await prepareSpendCallData(permission, spendAmount, recipient, { rpcUrl });
return callData;
}
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