Simple ERC20 token example.
The following code has not been tested nor audited.
Seek appropriate advice on regulatory compliance and your solution should have appropriate testing and auditing
Recommend reading: Points to consider when creating a fungible token (ERC20, ERC777)
There is an open issue to add a fixed supply ERC20 preset: https://github.com/OpenZeppelin/openzeppelin-contracts/issues/2377
This example smart contract merely sets a name, symbol and intial supply. All tokens are pre-assigned to the creator using the internal mint function.
SimpleToken.sol
// contracts/SimpleToken.sol
// SPDX-License-Identifier: MIT
pragma solidity ^0.6.2;
import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
/**
* @title SimpleToken
* @dev Very simple ERC20 Token example, where all tokens are pre-assigned to the creator.
* Note they can later distribute these tokens as they wish using `transfer` and other
* `ERC20` functions.
* Based on https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v2.5.1/contracts/examples/SimpleToken.sol
*/
contract SimpleToken is ERC20 {
/**
* @dev Constructor that gives msg.sender all of existing tokens.
*/
constructor(
string memory name,
string memory symbol,
uint256 initialSupply
) public ERC20(name, symbol) {
_mint(msg.sender, initialSupply);
}
}
Migration (Truffle)
2_deploy.js
// migrations/2_deploy.js
const SimpleToken = artifacts.require('SimpleToken');
module.exports = async function (deployer) {
await deployer.deploy(SimpleToken, 'SimpleToken', 'SIM', '10000000000000000000000');
};
Test
SimpleToken.test.js
// test/SimpleToken.test.js
// SPDX-License-Identifier: MIT
// Based on https://github.com/OpenZeppelin/openzeppelin-solidity/blob/v2.5.1/test/examples/SimpleToken.test.js
const { expect } = require('chai');
// Import utilities from Test Helpers
const { BN, expectEvent, expectRevert, constants } = require('@openzeppelin/test-helpers');
// Load compiled artifacts
const SimpleToken = artifacts.require('SimpleToken');
// Start test block
contract('SimpleToken', function ([ creator, other ]) {
const NAME = 'SimpleToken';
const SYMBOL = 'SIM';
const TOTAL_SUPPLY = new BN('10000000000000000000000');
beforeEach(async function () {
this.token = await SimpleToken.new(NAME, SYMBOL, TOTAL_SUPPLY, { from: creator });
});
it('retrieve returns a value previously stored', async function () {
// Use large integer comparisons
expect(await this.token.totalSupply()).to.be.bignumber.equal(TOTAL_SUPPLY);
});
it('has a name', async function () {
expect(await this.token.name()).to.be.equal(NAME);
});
it('has a symbol', async function () {
expect(await this.token.symbol()).to.be.equal(SYMBOL);
});
it('assigns the initial total supply to the creator', async function () {
expect(await this.token.balanceOf(creator)).to.be.bignumber.equal(TOTAL_SUPPLY);
});
});
Crowdsale
If you are looking for a crowdsale example, see: Simple ERC20 Crowdsale.
