Contract template

Universal crowdfunding

The crowdfunding token means that after the token is issued, any address can purchase tokens from the crowdfunding address using ETH.

The exchange ratio between token and ETH is set at the same time as the contract is deployed.

All crowdfunding contracts must be deployed after an ERC20 token has been successfully deployed, and a fixed amount of ERC20 contracts has been set in the deployment script

contract documents: AllowanceCrowdsale.sol (opens new window)

testing script : AllowanceCrowdsale.js (opens new window)

Deployment script: 9_deploy_AllowanceCrowdsale.js (opens new window)

Define the following variables when deploying the contract

uint256 rate               //Exchange ratio 1ETH how many ERC20 tokens to exchange
address payable wallet     //Address of the beneficiary receiving ETH
IERC20 token               //Tokens address
address tokenWallet        //The token is sent from this address

Methods erc20 was implemented after the crowdfunding contract was deployed

//Tokens in the sender's account must be approved for crowdfunding contracts after deployment  
token.approve(crowdsale.address, SOME_TOKEN_AMOUNT);

Calling methods

//Returns the token address
token() public view returns (IERC20)          
//Return beneficiary's address              
wallet() public view returns (address payable)              
//Return conversion ratio
rate() public view returns (uint256) 
//Returned sales
weiRaised() public view returns (uint256)         
//The token is purchased and sent to the specified address          
buyTokens(address beneficiary) public nonReentrant payable  
//Special methods
//Returns the existing address of the token
tokenWallet() public view returns (address)                 
//Check the number of tokens left in the quota
remainingTokens() public view returns (uint256)