Buy Methods

buy

Users can purchase a presale token using the buy method so that they can withdraw after the withdraw time. It is recommended to use the buyAndWithdraw method if withdraw time has passed. Otherwise, users could use the buy method.

Parameter

Argument	Type	Description
paymentMethod	String	The address of an ERC20 token that can be used to exchange for the presale token.
amount	String	The amount of payment token spent to buy the presale token.
signer	Signer	An instance to represent the wallet account.

Response

Field	Type	Description
type	number	The EIP-2718 type of this transaction.
chainId	number	The id of the network.
nonce	number	The nonce used as part of the proof-of-work to mine this block.
maxPriorityFeePerGas	BigNumber	The price (in wei) per unit of gas for this transaction.
maxFeePerGas	BigNumber	The maximum price (in wei) per unit of gas this transaction will pay for (the combined EIP-1559 block's base fee and this transaction's priority fee).
gasPrice	BigNumber	The price (in wei) per unit of gas this transaction will pay.
gasLimit	BigNumber	The maximum amount of gas that this block was permitted to use.
to	string	The address of the target.
value	BigNumber	The amount (in wei) this transaction is sending.
data	string	Transaction data.
accessList	AccessList	The AccessList to include; only available for EIP-2930 and EIP-1559 transactions.
hash	string	Transaction hash.
v	number	Values for the transaction's signature.
r	string	Values for the transaction's signature.
s	string	Values for the transaction's signature.
from	string	The sender address of the transaction.
confirmations	number	The number of blocks that have been mined (including the initial block) since this transaction.

Example

If the payment token is an erc20 token, we need to ensure the presale contract has enough allowance to spend the user's token. If not, developers can always use the following lines to ensure sufficient allowance:

const paymentToken = PAYMENT_METHOD
// assume PAYMENT_METHOD stores a payment method from the list 
// of payment methods returned by getPaymentMethods
const ZERO_ADDRESS = '0x0000000000000000000000000000000000000000'
if(paymentToken !== ZERO_ADDRESS){
    const allowance = await presaleSdk.getAllowance(paymentToken, await signer.getAddress());
    const amount = BigNumber.from(20)
    if(allowance.lt(amount)){
        await presaleSdk.increaseAllowance(paymentToken, amount.toString(), signer)
    }    
}

Then call the buy method:

await presaleSdk.buy(paymentToken, '20', signer)

Note:

There is no need to increase allowance through the above code snippet if the payment token is a native token of the specified chain

buyAndWithdraw

Users can purchase a presale token and automatically withdraw the purchased presale token. This method works only if the withdrawal time of the presale contract is passed.

Parameter

Argument	Type	Description
paymentMethod	String	The address of an ERC20 token that can be used to exchange for the presale token.
amount	String	The amount of payment token spent to buy the presale token.
signer	Signer	An instance to represent the wallet account.

Response

Field	Type	Description
buy	TransactionResponse	the transaction object generated from the buy step of this method
withdraw	TransactionResponse	the transaction object generated from the withdraw step of this method

TransactionResponse

Field	Type	Description
type	number	The EIP-2718 type of this transaction.
chainId	number	The id of the network.
nonce	number	The nonce used as part of the proof-of-work to mine this block.
maxPriorityFeePerGas	BigNumber	The price (in wei) per unit of gas for this transaction.
maxFeePerGas	BigNumber	The maximum price (in wei) per unit of gas this transaction will pay for (the combined EIP-1559 block's base fee and this transaction's priority fee).
gasPrice	BigNumber	The price (in wei) per unit of gas this transaction will pay.
gasLimit	BigNumber	The maximum amount of gas that this block was permitted to use.
to	string	The address of the target.
value	BigNumber	The amount (in wei) this transaction is sending.
data	string	Transaction data.
accessList	AccessList	The AccessList to include; only available for EIP-2930 and EIP-1559 transactions.
hash	string	Transaction hash.
v	number	Values for the transaction's signature.
r	string	Values for the transaction's signature.
s	string	Values for the transaction's signature.
from	string	The sender address of the transaction.
confirmations	number	The number of blocks that have been mined (including the initial block) since this transaction.

Example

const paymentToken = PAYMENT_METHOD
// assume PAYMENT_METHOD stores a payment method from the list 
// of payment methods returned by getPaymentMethods
const ZERO_ADDRESS = '0x0000000000000000000000000000000000000000'
if(paymentToken !== ZERO_ADDRESS){
    const allowance = await presaleSdk.getAllowance(paymentToken, await signer.getAddress());
    const amount = BigNumber.from(20)
    if(allowance.lt(amount)){
        const incrementAllowance = amount.sub(allowance).toString()
        await presaleSdk.increaseAllowance(paymentToken, incrementAllowance, signer)
    }    
}

Note:

There is no need to increase allowance through the above code snippet if the payment token is a native token of the specified chain.

Then call the buyAndWithdraw method:

const paymentToken = PAYMENT_METHOD
// assume PAYMENT_METHOD stores a payment method from the list 
// of payment methods returned by getPaymentMethods
await presaleSdk.buyAndWithdraw(paymentToken, '20', signer)