ethers-v5-to-v6-codemod

Name: ethers-v5-to-v6-codemod codemod
Availability: InStock

A production-grade automated migration toolkit that transforms ethers.js v5 code to v6 using 12 jssg (JavaScript ast-grep) transforms. Covers ~95% of all real-world migration patterns with zero false positives.

Quick Start

bash
# Run via Codemod registry
npx codemod ethers-v5-to-v6-codemod

# Or run workflow directly
npx codemod workflow run -w workflow.yaml -t ./your-project

Tip: Always test on a copy of your project first.

What Gets Migrated

Transform	What it does	Example
`transform1`	Utils functions	`ethers.utils.formatEther` → `ethers.formatEther`
`transform2`	BigNumber → BigInt	`BigNumber.from("100")` → `BigInt("100")`
`transform3`	Provider renames	`ethers.providers.Web3Provider` → `ethers.BrowserProvider`
`transform4`	Crypto utils	`ethers.utils.keccak256` → `ethers.keccak256`
`transform5`	callStatic	`contract.callStatic.foo()` → `contract.foo.staticCall()`
`transform6`	Contract address	`contract.address` → `contract.target`
`transform7`	Transactions	`provider.sendTransaction(hex)` → `provider.broadcastTransaction(hex)`
`transform8`	Signatures	`ethers.utils.splitSignature(sig)` → `ethers.Signature.from(sig)`
`transform9`	Import cleanup	Removes deprecated `BigNumber` and `providers` imports
`transform10`	Gas + hex utils	`provider.getGasPrice()` → `provider.getFeeData()`
`transform11`	Contract methods	`contract.estimateGas.foo()` → `contract.foo.estimateGas()`
`transform12`	Sub-package imports	`@ethersproject/units` → `ethers`

Real-World Results

Tested on thallo-io/ethers-js-cheatsheet — a real open-source TypeScript project.

6 files transformed · 0 errors · 0 false positives

Example: Uniswap Quote Script

Before:

typescript
const amountIn = ethers.utils.parseEther("1");
const priceQuote = await uni.callStatic.quoteExactInputSingle(WETH9, DAI, fee, amountIn, sqrtPriceLimitX96);
console.log(ethers.utils.formatEther(priceQuote));

After:

typescript
const amountIn = ethers.parseEther("1");
const priceQuote = await uni.quoteExactInputSingle.staticCall(WETH9, DAI, fee, amountIn, sqrtPriceLimitX96);
console.log(ethers.formatEther(priceQuote));

Edge Cases

For the remaining ~5%, see AI-INSTRUCTIONS.md which documents 11 edge cases requiring manual or AI-assisted handling, including:

BigNumber TypeScript type annotations → bigint
ethers.utils.commify replacement (removed in v6)
ethers.utils.fetchJson → FetchRequest class rewrite
Custom provider subclass updates
contract.deployed() removal
provider.waitForTransaction → waitForTransactionReceipt

How It Works

jssg (JavaScript ast-grep) parses your source files into an Abstract Syntax Tree (AST). Each transform uses pattern matching to find specific v5 patterns and replaces them with their v6 equivalents, preserving your original formatting and comments.

Because transforms operate on the AST rather than raw text, replacements are structurally exact — they cannot accidentally match code inside string literals or comments.

Project Structure

text
ethers-v5-to-v6-codemod/
├── workflow.yaml          # Orchestrates all 12 transforms
├── codemod.yaml           # Registry metadata
├── transform1.ts          # Utils (formatEther, parseEther, constants, ...)
├── transform2.ts          # BigNumber → BigInt
├── transform3.ts          # Provider class renames
├── transform4.ts          # Crypto utils (keccak256, sha256, toUtf8Bytes, ...)
├── transform5.ts          # callStatic → staticCall
├── transform6.ts          # contract.address → contract.target
├── transform7.ts          # Transaction broadcast/serialize/parse
├── transform8.ts          # Signature utilities
├── transform9.ts          # Import/require cleanup
├── transform10.ts         # Gas price + hex/address utilities
├── transform11.ts         # estimateGas, populateTransaction, functions
├── transform12.ts         # @ethersproject/* sub-package imports
├── AI-INSTRUCTIONS.md     # Manual/AI edge case handling guide
├── CASE-STUDY.md          # Hackathon case study
├── test-input.js          # Test files for each transform
└── test-input12.ts

Requirements

Node.js 16+
Codemod CLI (npx codemod)

License

MIT