Implementing a Weighted Voting DApp with ERC20 Tokens on Ethereum

The tutorial begins by reviewing basic token concepts on Ethereum, such as ERC20 tokens that can represent assets like gold, company shares, or loyalty points, and explains how these tokens are implemented using smart contracts.

It then introduces a weighted voting system where each voter’s voting power is proportional to the number of tokens they hold. The Solidity contract is redesigned to include a struct voter that stores the voter’s address, total tokens purchased, and an array of tokens used per candidate.

Key contract functions are presented:

function buy() payable public returns (uint) – allows users to purchase tokens by sending Ether, calculates the amount of tokens based on the token price, updates balances, and returns the purchased amount.

function voteForCandidate(bytes32 candidate, uint votesInTokens) public – enables weighted voting by specifying the candidate and the number of tokens to allocate, checks that the voter has enough available tokens, updates the candidate’s vote count, and records the tokens used.

function transferTo(address account) public – demonstrates how the contract’s Ether balance can be transferred to an external account (note: the example lacks access control).

The article also shows how to initialize the contract with total token supply, token price, and a list of candidates via the constructor, and provides a migration script that deploys the contract using Truffle with parameters such as 10000 total tokens and a price of 0.01 ether .

Deployment steps are detailed, including compiling with truffle compile , migrating with truffle migrate , and interacting via the Truffle console to query votes, total tokens, tokens sold, and to execute token purchases and weighted votes.

Finally, the guide outlines the front‑end integration using a Webpack‑based project. JavaScript functions create a contract instance, populate candidate names and vote counts, display token statistics, and implement buyTokens and lookupVoterInfo to interact with the contract from a web page.