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BatchCommonSteps

Function definition​

Define a function called batchCreateStreams that takes a parameter perStreamAmount and returns an array of ids for the created streams:

function batchCreateStreams(uint128 perStreamAmount) public returns (uint256[] memory streamIds) {
  // ...
}

Batch size​

Next, declare a batch size, which is needed to calculate the transfer amount:

// Create a batch of two streams
uint256 batchSize = 2;

// Calculate the combined amount of DAI to transfer to this contract
uint256 transferAmount = perStreamAmount * batchSize;

ERC-20 steps​

To create a stream, the caller must approve the creator contract to pull the tokens from the calling address's account. Then, we have to also approve the Batch contract to pull the tokens that the creator contract will be in possession of after they are transferred from the calling address (you):

// Transfer the provided amount of DAI tokens to this contract
DAI.transferFrom(msg.sender, address(this), transferAmount);

// Approve the Batch contract to spend DAI
DAI.approve(address(BATCH_LOCKUP), transferAmount);

For more guidance on how to approve and transfer ERC-20 tokens, see this article on the Ethereum website.