TimeLockedWallet

This is my learning project in Solidity. It is a simple smart contract that lets a user deposit ETH and withdraw it only after a specific time.

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💡 Idea

I wanted to practice how time works in smart contracts. The main idea is very simple: 1. A user sends some ETH to the contract. 2. Sets the time when it can be unlocked. 3. If the time is not reached yet → you cannot withdraw. 4. If the time has passed → you can withdraw your ETH.

I used this project to learn about block.timestamp, mapping, events, and how to test time with Hardhat.

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⚙️ Functions • createDeposit(uint unlockTime) — creates a deposit (must be in the future). • withdrawDeposit(uint index) — lets you withdraw after the unlock time.

Custom errors for checks: • StillLocked — time not reached. • AlreadyWithdrawn — funds already taken. • InvalidIndex — wrong deposit index.

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🧪 Tests (Hardhat)

I wrote simple unit tests to cover main cases: 1. Deposit is created and emits DepositCreated. 2. Withdrawal before unlock time → reverts with StillLocked. 3. Successful withdrawal after unlock time → emits Withdrawn. 4. Second withdrawal → reverts with AlreadyWithdrawn.

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🧰 Tools and tech • Solidity ^0.8.20 • Hardhat • Chai + Ethers.js • @nomicfoundation/hardhat-toolbox (for time control)

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🚀 How to run npm install npx hardhat compile npx hardhat test