feat: generate separate testnet token list (#40)

* feat: generate separate testnet token list

* style: format generated testnet tokenlist changes

Author: crumb-trail

README.md

@@ -1,18 +1,19 @@
 # MegaETH Token List
 
-The official token registry for the MegaETH ecosystem. This repository maintains a curated list of tokens deployed on MegaETH and their corresponding addresses on other chains for bridging and cross-chain tracking.
+The official token registry for the MegaETH ecosystem. This repository maintains curated token lists for MegaETH and their corresponding addresses on other chains for bridging and cross-chain tracking.
 
-The generated tokenlist follows the [Uniswap Token List](https://github.com/Uniswap/token-lists) standard with MegaETH-specific extensions for tracking bridge mechanics and token origins.
+The generated tokenlists follow the [Uniswap Token List](https://github.com/Uniswap/token-lists) standard with MegaETH-specific extensions for tracking bridge mechanics and token origins.
 
 ## Supported Chains
 
-| Chain    | Chain ID | Type   | Description                             |
-| -------- | -------- | ------ | --------------------------------------- |
-| Ethereum | 1        | L1     | Ethereum mainnet                        |
-| MegaETH  | 4326     | L2     | MegaETH mainnet                         |
-| Solana   | -        | Source | Non-EVM source chain for bridged assets |
+| Chain           | Chain ID | Type   | Description                             |
+| --------------- | -------- | ------ | --------------------------------------- |
+| Ethereum        | 1        | L1     | Ethereum mainnet                        |
+| MegaETH         | 4326     | L2     | MegaETH mainnet                         |
+| MegaETH Testnet | 6343     | L2     | MegaETH testnet                         |
+| Solana          | -        | Source | Non-EVM source chain for bridged assets |
 
-> **Note:** Only EVM chains (Ethereum, MegaETH) appear in the generated tokenlist. Non-EVM chains like Solana are tracked as source chains — their addresses appear in the `extensions` field.
+> **Note:** This repo produces separate outputs for mainnet and testnet. The mainnet tokenlist includes only Ethereum + MegaETH mainnet entries. Testnet tokens are emitted only in the separate testnet list to avoid contaminating production consumers.
 
 ---
 
@@ -25,6 +26,11 @@ The generated tokenlist follows the [Uniswap Token List](https://github.com/Unis
 3. Add `logo.svg` or `logo.png` (256×256 recommended)
 4. Submit a PR
 
+### Generated Outputs
+
+- `megaeth.tokenlist.json` — mainnet list (Ethereum + MegaETH mainnet)
+- `megaeth.testnet.tokenlist.json` — testnet list (MegaETH testnet only)
+
 ---
 
 ## Token Data Schema
@@ -41,6 +47,15 @@ The generated tokenlist follows the [Uniswap Token List](https://github.com/Unis
 
 ### Per-Chain Fields
 
+Each chain entry in `tokens` supports.
+
+Supported keys today:
+
+- `ethereum`
+- `megaeth`
+- `megaeth_testnet`
+- `solana` (source tracking only, not emitted directly into tokenlists)
+
 Each chain entry in `tokens` supports:
 
 | Field       | Type    | Description                                                      |

megaeth.testnet.tokenlist.json

@@ -0,0 +1,10 @@
+{
+  "name": "MegaETH Testnet Token List",
+  "timestamp": "2026-04-22T00:58:21.755Z",
+  "version": {
+    "major": 1,
+    "minor": 0,
+    "patch": 0
+  },
+  "tokens": []
+}

megaeth.tokenlist.json

@@ -1,6 +1,6 @@
 {
   "name": "MegaETH Token List",
-  "timestamp": "2026-02-24T01:41:27.206Z",
+  "timestamp": "2026-04-22T00:58:21.752Z",
   "version": {
     "major": 1,
     "minor": 0,

src/__tests__/generate.test.ts

@@ -1,4 +1,4 @@
-import { CHAINS, CHAIN_IDS, L2_TO_L1 } from '../chains';
+import { CHAINS, CHAIN_IDS, L2_TO_L1, TOKENLIST_TARGET_CHAINS } from '../chains';
 import { generate } from '../generate';
 
 describe('Chain Configuration', () => {
@@ -15,10 +15,21 @@ describe('Chain Configuration', () => {
   test('MegaETH L2 maps to Ethereum L1', () => {
     expect(L2_TO_L1.megaeth).toBe('ethereum');
   });
+
+  test('MegaETH testnet chain ID is 6343', () => {
+    expect(CHAIN_IDS.megaeth_testnet).toBe(6343);
+    expect(CHAINS.megaeth_testnet.id).toBe(6343);
+  });
+
+  test('tokenlist targets separate mainnet and testnet chains', () => {
+    expect(TOKENLIST_TARGET_CHAINS.mainnet).toEqual(['ethereum', 'megaeth']);
+    expect(TOKENLIST_TARGET_CHAINS.testnet).toEqual(['megaeth_testnet']);
+  });
 });
 
 describe('Token List Generation', () => {
   const tokenList = generate();
+  const testnetTokenList = generate('testnet');
 
   test('generates valid token list structure', () => {
     expect(tokenList).toHaveProperty('name', 'MegaETH Token List');
@@ -28,6 +39,14 @@ describe('Token List Generation', () => {
     expect(Array.isArray(tokenList.tokens)).toBe(true);
   });
 
+  test('generates separate testnet token list structure', () => {
+    expect(testnetTokenList).toHaveProperty('name', 'MegaETH Testnet Token List');
+    expect(testnetTokenList).toHaveProperty('timestamp');
+    expect(testnetTokenList).toHaveProperty('version');
+    expect(testnetTokenList).toHaveProperty('tokens');
+    expect(Array.isArray(testnetTokenList.tokens)).toBe(true);
+  });
+
   test('version has correct structure', () => {
     expect(tokenList.version).toHaveProperty('major');
     expect(tokenList.version).toHaveProperty('minor');
@@ -58,14 +77,12 @@ describe('Token List Generation', () => {
     }
   });
 
-  test('native tokens have isOrigin: true', () => {
-    const nativeTokens = tokenList.tokens.filter((t) => t.extensions.isOrigin);
-    expect(nativeTokens.length).toBeGreaterThan(0);
+  test('origin tokens have isOrigin: true', () => {
+    const originTokens = tokenList.tokens.filter((t) => t.extensions.isOrigin);
+    expect(originTokens.length).toBeGreaterThan(0);
 
-    for (const token of nativeTokens) {
+    for (const token of originTokens) {
       expect(token.extensions.isOrigin).toBe(true);
-      expect(token.extensions.bridgeAddress).toBeUndefined();
-      expect(token.extensions.bridgeType).toBeUndefined();
     }
   });
 
@@ -74,7 +91,7 @@ describe('Token List Generation', () => {
 
     for (const token of tokensWithLogos) {
       expect(token.logoURI).toMatch(
-        /^https:\/\/raw\.githubusercontent\.com\/megaeth-labs\/mega-tokenlist\/main\/data\/\w+\/logo\.(svg|png)$/
+        /^https:\/\/raw\.githubusercontent\.com\/megaeth-labs\/mega-tokenlist\/main\/data\/.+\/logo\.(svg|png)$/
       );
     }
   });
@@ -87,10 +104,16 @@ describe('Token List Generation', () => {
     expect(chainIds).toEqual([1, 4326]);
   });
 
-  test('WETH token exists only on MegaETH', () => {
+  test('WETH token includes a MegaETH mainnet entry', () => {
     const wethTokens = tokenList.tokens.filter((t) => t.symbol === 'WETH');
-    expect(wethTokens.length).toBe(1);
-    expect(wethTokens[0].chainId).toBe(4326);
-    expect(wethTokens[0].extensions.isOrigin).toBe(true);
+    expect(wethTokens.some((t) => t.chainId === 4326)).toBe(true);
+  });
+
+  test('mainnet token list excludes testnet chain ids', () => {
+    expect(tokenList.tokens.every((t) => t.chainId !== 6343)).toBe(true);
+  });
+
+  test('testnet token list only contains testnet chain ids', () => {
+    expect(testnetTokenList.tokens.every((t) => t.chainId === 6343)).toBe(true);
   });
 });

src/chains.ts

@@ -6,31 +6,42 @@ export const CHAINS = {
     name: 'Ethereum',
     layer: 1,
     evmCompatible: true,
+    environment: 'mainnet',
   },
   megaeth: {
     id: 4326,
     name: 'MegaETH',
     layer: 2,
     evmCompatible: true,
+    environment: 'mainnet',
+  },
+  megaeth_testnet: {
+    id: 6343,
+    name: 'MegaETH Testnet',
+    layer: 2,
+    evmCompatible: true,
+    environment: 'testnet',
   },
   solana: {
     id: null, // Non-EVM chain, uses string identifier
     name: 'Solana',
     layer: 1,
     evmCompatible: false,
+    environment: 'mainnet',
   },
 } as const
 
 export type Chain = keyof typeof CHAINS
-export type EvmChain = 'ethereum' | 'megaeth'
+export type EvmChain = 'ethereum' | 'megaeth' | 'megaeth_testnet'
 export type SourceChain = 'solana' // Non-EVM chains used only for source tracking
 export type L1Chain = 'ethereum'
-export type L2Chain = 'megaeth'
+export type L2Chain = 'megaeth' | 'megaeth_testnet'
 
 // Chain ID lookup (EVM chains only - used for tokenlist generation)
 export const CHAIN_IDS: Record<EvmChain, number> = {
   ethereum: 1,
   megaeth: 4326,
+  megaeth_testnet: 6343,
 }
 
 // Source chains (non-EVM) - used for tracking bridged asset origins
@@ -39,4 +50,15 @@ export const SOURCE_CHAINS: readonly SourceChain[] = ['solana'] as const
 // L2 to L1 mapping (for bridge relationships)
 export const L2_TO_L1: Record<L2Chain, L1Chain> = {
   megaeth: 'ethereum',
+  megaeth_testnet: 'ethereum',
+}
+
+export type TokenListTarget = 'mainnet' | 'testnet'
+
+export const TOKENLIST_TARGET_CHAINS: Record<
+  TokenListTarget,
+  readonly EvmChain[]
+> = {
+  mainnet: ['ethereum', 'megaeth'],
+  testnet: ['megaeth_testnet'],
 }

src/generate.ts

@@ -3,8 +3,10 @@ import * as path from 'path'
 import {
   CHAIN_IDS,
   SOURCE_CHAINS,
+  TOKENLIST_TARGET_CHAINS,
   type EvmChain,
   type SourceChain,
+  type TokenListTarget,
 } from './chains'
 import type {
   Mechanism,
@@ -15,7 +17,10 @@ import type {
 } from './types'
 
 const DATA_DIR = path.join(__dirname, '..', 'data')
-const OUTPUT_FILE = path.join(__dirname, '..', 'megaeth.tokenlist.json')
+const OUTPUT_FILES: Record<TokenListTarget, string> = {
+  mainnet: path.join(__dirname, '..', 'megaeth.tokenlist.json'),
+  testnet: path.join(__dirname, '..', 'megaeth.testnet.tokenlist.json'),
+}
 const LOGO_BASE_URL =
   'https://raw.githubusercontent.com/megaeth-labs/mega-tokenlist/main/data'
 
@@ -103,7 +108,7 @@ function inferMechanism(
   return 'unknown'
 }
 
-export function generate(): TokenList {
+export function generate(target: TokenListTarget = 'mainnet'): TokenList {
   // Read all token directories
   const tokenDirs = fs
     .readdirSync(DATA_DIR)
@@ -114,6 +119,7 @@ export function generate(): TokenList {
     .sort()
 
   const tokens: TokenListToken[] = []
+  const includedChains = new Set<EvmChain>(TOKENLIST_TARGET_CHAINS[target])
 
   for (const symbol of tokenDirs) {
     const tokenDir = path.join(DATA_DIR, symbol)
@@ -126,8 +132,9 @@ export function generate(): TokenList {
     for (const [chain, chainToken] of Object.entries(tokenData.tokens)) {
       if (!chainToken?.address) continue
 
-      const chainId = CHAIN_IDS[chain as EvmChain]
-      if (!chainId) continue
+      const evmChain = chain as EvmChain
+      const chainId = CHAIN_IDS[evmChain]
+      if (!chainId || !includedChains.has(evmChain)) continue
 
       const isOrigin = chainToken.isOrigin === true
       const mechanism = inferMechanism(chainToken, isOrigin)
@@ -189,7 +196,10 @@ export function generate(): TokenList {
   })
 
   const tokenList: TokenList = {
-    name: 'MegaETH Token List',
+    name:
+      target === 'mainnet'
+        ? 'MegaETH Token List'
+        : 'MegaETH Testnet Token List',
     timestamp: new Date().toISOString(),
     version: {
       major: 1,
@@ -204,7 +214,12 @@ export function generate(): TokenList {
 
 // Main execution
 if (require.main === module) {
-  const tokenList = generate()
-  fs.writeFileSync(OUTPUT_FILE, JSON.stringify(tokenList, null, 2))
-  console.log(`Generated ${OUTPUT_FILE} with ${tokenList.tokens.length} tokens`)
+  for (const target of ['mainnet', 'testnet'] as const) {
+    const tokenList = generate(target)
+    const outputFile = OUTPUT_FILES[target]
+    fs.writeFileSync(outputFile, JSON.stringify(tokenList, null, 2))
+    console.log(
+      `Generated ${outputFile} with ${tokenList.tokens.length} tokens`
+    )
+  }
 }