Utils

To make the process of creating smart sessions easier, we provide a set of helper functions.

createContractPermission

This helper function is used to create a permission for a smart contract function.

Example

import { createContractPermission } from "@0xsequence/connect";

const AAVE_V3_POOL_ADDRESS_ARBITRUM = '0x794a61358D6845594F94dc1DB02A252b5b4814aD'

const permission = createContractPermission({
    address: AAVE_V3_POOL_ADDRESS_ARBITRUM,
    functionSignature: 'function supply(address asset, uint256 amount, address onBehalfOf, uint16 referralCode)',
    rules: [
        {
            param: 'asset',
            type: 'address',
            condition: 'EQUAL',
            value: USDC_ADDRESS_ARBITRUM
        },
        {
            param: 'amount',
            type: 'uint256',
            condition: 'LESS_THAN_OR_EQUAL',
            value: parseUnits('1', 6),
            cumulative: true
        }
    ]
});

Params

type CreateContractPermissionOptions = {
  /** The address of the target contract. */
  address: Address

  /**
   * The human-readable function signature.
   * Example: 'function transfer(address to, uint256 amount)'
   */
  functionSignature?: string

  /** An array of rules to apply to the function's arguments. */
  rules?: Rule[]

  /**
   * If true, this function can only be successfully called once during the session.
   * @default false
   */
  onlyOnce?: boolean
}

address

The address of the target contract.

functionSignature

The human-readable function signature.

rules

An array of rules to apply to the function’s arguments.

type Rule = {
  /** The name of the parameter from the function signature (e.g., 'to', 'amount'). */
  param: string

  /** The type of the parameter (address, uint256, etc.). */
  type: ParamType

  /** The comparison to perform on the parameter (EQUAL, NOT_EQUAL, GREATER_THAN_OR_EQUAL, LESS_THAN_OR_EQUAL). */
  condition: RuleCondition

  /** The value to compare against. Must match the `type`. */
  value: string | number | bigint | boolean

  /**
   * Determines if the rule's value is a cumulative total across all calls to this function.
   * @example
   * For a `transfer` function on an ERC20 token, if we set a rule for the `amount` parameter to be 10 and we set `cumulative`
   * to `true` then the dApp can make as many transfer calls as it wants but in total it cannot transfer more than 10 tokens.
   * If `cumulative` is `false` then the dApp can transfer 10 tokens as many times as it wants if other conditions are met.
   * This makes sense only for number values like amount of transfers, etc.
   * @default true 
   */
  cumulative?: boolean
}

onlyOnce

If true, this function can only be successfully called once during the session.

Return type

Returns a Permission.

type Permission = {
  target: Address.Address
  rules: ParameterRule[]
}

createContractPermissions

Same as createContractPermission, but it creates multiple permissions for the same contract.

Example

import { createContractPermissions } from "@0xsequence/connect";

const permissions = createContractPermissions({
    address: AAVE_V3_POOL_ADDRESS_ARBITRUM,
    functionSignatures: [
        'function supply(address asset, uint256 amount, address onBehalfOf, uint16 referralCode)',
        'function withdraw(address asset, uint256 amount, address to)',
    ],
    rules: [
        {
            param: 'asset',
            type: 'address',
            condition: 'EQUAL',
            value: USDC_ADDRESS_ARBITRUM
        }
        {
            param: 'amount',
            type: 'uint256',
            condition: 'LESS_THAN_OR_EQUAL',
            value: parseUnits('1', 6),
            cumulative: true
        }
    ]
});

Params

/**
 * The options object for creating permissions.
 */
export type CreateContractPermissionsOptions = {
  /** The address of the target contract. */
  address: Address

  /** An array of permissions for one or more functions on this contract. */
  functions?: FunctionPermission[] | undefined | null
}

address

The address of the target contract.

functions

An array of FunctionPermission

type FunctionPermission = {
  /**
   * The human-readable function signature.
   * Example: 'function transfer(address to, uint256 amount)'
   */
  functionSignature: string

  /** An array of rules to apply to the function's arguments. */
  rules?: Rule[]

  /**
   * If true, this function can only be successfully called once during the session.
   * @default false
   */
  onlyOnce?: boolean
}

Return type

Returns a Permission[].

type Permission = {
  target: Address.Address
  rules: ParameterRule[]
}

See these utilities in action here.