ERC4626 and slippage

Question

The newly introduced ERC4626 standard provides functions for depositing and withdrawing funds to a vault, but it is unclear to me how the designers envisioned adding custom slippage rates from the function method:

function deposit(uint256 assets, address receiver) public virtual returns (uint256 shares);

There's mention that slippage rates should be included in the preview functions (e.g., previewDeposit), but what would the best-practice solution look like to add per-interaction slippage with this? My only thoughts here are:

• somehow set-it in a mapping prior to calling the deposit function but that seems unnecessarily cumbersome.
• implement standard slippage of e.g., 3% and add a custom deposit function that does support slippage

In any case, neither of these would be 'standard'.

Answer 1

You can customise the inner workings of the deposit function as you wish. Like adding a standard slippage

uint slippage = 100; // = 1% slippage

function deposit(uint256 assets, address receiver) public virtual returns (uint256 shares){
    //... code
    uint amountWithSlippage = amount + (amount / slippage); using amounts under 100 wei would make transaction revert, add an if statement to make this possible
    //... code

}

Or add a fucntion where users can edit their slippage themselves

mapping(address => uint) slippages;

function setSlippage(uint _slippage) public {
    slippages[msg.sender] = _slippage;

function deposit(uint256 assets, address receiver) public virtual returns (uint256 shares){

     //... code
    uint slippage = slippages[msg.sender];
    uint amountWithSlippage = amount + (amount / slippage);
    //... code