NEP21 is based on:
https://github.com/near/near-sdk-rs/blob/ab5c01ca4c61a6414484b69302b84e5ce3113f2f/examples/fungible-token/src/lib.rs
The aim of the contract is to enable the wrapping of the native Ⓝ token into a NEP21 compatible token. It's the equivalent of wrapping ETH into wETH via the WETH. This contract is based on the functionality of the WETH9 and WETH10 Solidity smart contracts.
The following methods are available for minting:
deposit(amount)deposit_to(recipient, amount)
deposit(amount) just proxies through to deposit_to(recipient, amount) where recipient will be set to env::predecessor_account_id().
When using deposit_to, the following requirements apply:
- Recipient cannot be the wNear contract - to stop people accidentally losing money
- Recipient needs to be a valid account Id
- Amount must be a positive integer
Both deposit methods will require an attached deposit that covers the storage requirements and the amount of wNear tokens being minted.
The following methods are available for unwrapping wNear:
withdraw(amount)withdraw_to(recipient, amount)withdraw_from(owner_id, recipient, amount)
Like deposit(), withdraw() is the simplest and can be called by the owner of wNear tokens to claim the underlying Near Ⓝ asset.
When using withdraw_to, the following requirements apply:
- Recipient cannot be the wNear contract - to stop people accidentally losing money
- Recipient needs to be a valid account Id
- Amount must be a positive integer
Caller must have a balance that is greater than or equal to amount.
withdraw_from (like withdraw_to) comes from WETH10 and allows an approved account to unwrap wNear from an owner who has a wNear balance.