Optimism L1 ↔ L2 Bridge & Forced Transaction Scripts

Scripts for interacting with Optimism's Layer 2: ETH bridging and forced transactions via the Portal contract.

🚀 Quick Start

Prerequisites

• Node.js (v16+)
• Local OP Stack deployment
• Test ETH on L1

Setup

git clone <your-repo>
cd forced-deposit
npm install

Create a .env file with your configuration (see .env.example).

📋 Available Scripts

Script	Command	Description
ETH Bridge	npm run bridge-eth	Bridge ETH from L1 to L2 via Standard Bridge
Forced Transaction	npm run forced-tx	Send forced transaction via L1 Portal (no ETH)
Forced Transaction (with ETH)	npm run forced-tx-value	Transfer ETH on L2 via forced transaction from L1
Forced Transaction (Fail Case)	npm run forced-tx-failcase	Test forced transaction with insufficient funds

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🌉 ETH Bridge (depositEthTo.js)

Bridges ETH from L1 to L2 using the L1StandardBridge contract.

Usage: npm run bridge-eth

Features: Monitors bridge events, verifies L2 balance updates, computes cross-domain message hashes.

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💪 Forced Transaction Scripts

1. Basic Forced Transaction (forcedTx.js)

Sends a forced transaction via L1 Portal to execute on L2 (no ETH transfer).

Usage: npm run forced-tx

Flow: Deploy storage contract on L2 → Send forced tx from L1 → Verify execution on L2

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2. Forced Transaction with ETH Transfer (forcedTx_value.js)

Purpose: Transfer ETH on L2 from one address to another via a forced transaction sent on L1.

How it works:

1. Forced transaction is sent to L1 Portal
2. The inner transaction (processed on L2) transfers ETH to the target address
3. Verifies both contract state and balance changes on L2

Usage: npm run forced-tx-value

Configuration:

const AMOUNT_ETH = "0.001"; // ETH amount to transfer on L2

Key Points:

• Forced transaction sent on L1 via Portal
• Inner transaction executes on L2 and transfers ETH
• Verifies ETH was received at the target address on L2
• Uses separate ABI/bytecode files (./abi/storage, ./utils/storage_bytecode)

When to Use: When you need to transfer ETH on L2 from one address to another using a forced transaction initiated on L1.

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3. Forced Transaction Fail Case (forcedTx_value_failcase.js)

Purpose: Demonstrate forced transaction inclusion even when the transaction fails due to insufficient funds on L2.

How it works:

1. Creates a second wallet (wallet2) with a random private key
2. Transfers ETH from wallet1 to wallet2 on L1
3. Wallet2 sends a forced transaction via L1 Portal to transfer ETH to a random address
4. The transaction is processed on L2 but fails (wallet2 has 0 ETH on L2 for gas)
5. Verifies the transaction was included and processed on L2 (even though it failed)

Usage: npm run forced-tx-failcase

Key Points:

• Demonstrates forced inclusion: transactions are included on L2 even if they fail
• Wallet2 has ETH on L1 but 0 ETH on L2
• The forced transaction is processed on L2 but fails due to insufficient gas
• Verification checks for transaction presence (not just success)
• Proves that forced transactions bypass the sequencer and are guaranteed inclusion

When to Use: When testing that forced transactions are always included on L2, regardless of whether they succeed or fail. This is crucial for understanding censorship resistance in Optimism.