commentary ERC20.md

Commentary on ERC20

Source: ethereum.org

• Methods:

  - name(): OPTIONAL, Returns the name of the token - e.g. "MyToken". ALSO: `function name() public view returns (string)`
  - symbol(): OPTIONAL, Returns the symbol of the token. E.g. “HIX”. ALSO: `function symbol() public view returns (string)`
  - decimals(): OPTIONAL, Returns the number of decimals the token uses - e.g. 8, means to divide the token amount by 100000000 to get its user representation. ALSO: `function decimals() public view returns (uint8)`
  - totalSupply(): Returns the total token supply. ALSO: `function totalSupply() public view returns (uint256)`
  - balanceOf(): Returns the account balance of an account. ALSO: `function balanceOf(address _owner) public view returns (uint256 balance)`
  - transfer(): Transfers _value amount of tokens to address _to, and MUST fire the Transfer event. The function SHOULD throw if the message caller’s account balance does not have enough tokens to spend. ALSO: `function transfer(address _to, uint256 _value) public returns (bool success)`
  - transferFrom(): Transfers `_value` amount of tokens from address `_from` to address `_to`, and MUST fire the Transfer event. The transferFrom method is used for a withdraw workflow, allowing contracts to transfer tokens on your behalf. ALSO: `function transferFrom(address _from, address _to, uint256 _value) public returns (bool success)`
  - approve(): Allows `_spender` to withdraw from your account multiple times, up to the `_value` amount. If this function is called again it overwrites the current allowance with `_value`. Clients SHOULD make sure to create user interfaces in such a way that they set the allowance first to 0 before setting it to another value for the same spender. ALSO: `function approve(address _spender, uint256 _value) public returns (bool success)`
  - allowance(): Returns the amount which _spender is still allowed to withdraw from `_owner`. ALSO: `function allowance(address _owner, address _spender) public view returns (uint256 remaining)`

• Events:

- Transfer: MUST trigger when tokens are transferred, including zero value transfers.
event Transfer(address indexed _from, address indexed _to, uint256 _value)

- Approval: MUST trigger on any successful call to approve(address _spender, uint256 _value).
event Approval(address indexed _owner, address indexed _spender, uint256 _value)

Implementations:

• Openzeppelin Implementation: Click here
• ConcenSys Implementation: Click here (Disadvantage: They are not gas optimized as much Openzeppelin contracts are bcoz they use unchecked keyword to optimize).