Adds /destinationTokens route [SLT-204]

packages/rest-api/.eslintrc.js

@@ -5,6 +5,13 @@ module.exports = {
       files: ['jest.config.js'],
       rules: {
         'prettier/prettier': 'off',
+        'guard-for-in': 'off',
+      },
+    },
+    {
+      files: ['**/*.ts', '**/*.tsx'],
+      rules: {
+        'guard-for-in': 'off',
       },
     },
   ],

packages/rest-api/src/constants/bridgeable.ts

@@ -1,7 +1,6 @@
 import { BridgeableToken } from '../types'
 import { CHAINS } from './chains'
-
-const ZeroAddress = '0x0000000000000000000000000000000000000000'
+import { ZeroAddress } from '.'
 
 export const GOHM: BridgeableToken = {
   addresses: {

packages/rest-api/src/constants/index.ts

@@ -3,3 +3,6 @@ export const VALID_BRIDGE_MODULES = [
   'SynapseCCTP',
   'SynapseRFQ',
 ]
+
+export const ZeroAddress = '0x0000000000000000000000000000000000000000'
+export const EthAddress = '0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE'

packages/rest-api/src/controllers/destinationTokensController.ts

@@ -0,0 +1,29 @@
+import { validationResult } from 'express-validator'
+
+import { tokenAddressToToken } from '../utils/tokenAddressToToken'
+import { BRIDGE_ROUTE_MAPPING } from '../utils/bridgeRouteMapping'
+
+export const destinationTokensController = async (req, res) => {
+  const errors = validationResult(req)
+  if (!errors.isEmpty()) {
+    return res.status(400).json({ errors: errors.array() })
+  }
+
+  try {
+    const { fromChain, fromToken } = req.query
+
+    const fromTokenInfo = tokenAddressToToken(fromChain.toString(), fromToken)
+
+    const constructedKey = `${fromTokenInfo.symbol}-${fromChain}`
+
+    const options = BRIDGE_ROUTE_MAPPING[constructedKey]
+
+    res.json(options)
+  } catch (err) {
+    res.status(500).json({
+      error:
+        'An unexpected error occurred in /destinationTokens. Please try again later.',
+      details: err.message,
+    })
+  }
+}

packages/rest-api/src/routes/destinationTokensRoute.ts

@@ -0,0 +1,38 @@
+import express from 'express'
+import { check } from 'express-validator'
+import { isAddress } from 'ethers/lib/utils'
+
+import { CHAINS_ARRAY } from '../constants/chains'
+import { showFirstValidationError } from '../middleware/showFirstValidationError'
+import { destinationTokensController } from '../controllers/destinationTokensController'
+import { isTokenAddress } from '../utils/isTokenAddress'
+import { isTokenSupportedOnChain } from '../utils/isTokenSupportedOnChain'
+
+const router = express.Router()
+
+router.get(
+  '/',
+  [
+    check('fromChain')
+      .exists()
+      .withMessage('fromChain is required')
+      .isNumeric()
+      .custom((value) => CHAINS_ARRAY.some((c) => c.id === Number(value)))
+      .withMessage('Unsupported fromChain'),
+    check('fromToken')
+      .exists()
+      .withMessage('fromToken is required')
+      .custom((value) => isAddress(value))
+      .withMessage('Invalid fromToken address')
+      .custom((value) => isTokenAddress(value))
+      .withMessage('Unsupported fromToken address')
+      .custom((value, { req }) =>
+        isTokenSupportedOnChain(value, req.query.fromChain as string)
+      )
+      .withMessage('Token not supported on specified chain'),
+  ],
+  showFirstValidationError,
+  destinationTokensController
+)
+
+export default router

packages/rest-api/src/routes/index.ts

@@ -9,6 +9,7 @@ import getSynapseTxIdRoute from './getSynapseTxIdRoute'
 import getBridgeTxStatusRoute from './getBridgeTxStatusRoute'
 import getDestinationTxRoute from './getDestinationTxRoute'
 import tokenListRoute from './tokenListRoute'
+import destinationTokensRoute from './destinationTokensRoute'
 
 const router = express.Router()
 
@@ -21,5 +22,6 @@ router.use('/getSynapseTxId', getSynapseTxIdRoute)
 router.use('/getBridgeTxStatus', getBridgeTxStatusRoute)
 router.use('/getDestinationTx', getDestinationTxRoute)
 router.use('/tokenList', tokenListRoute)
+router.use('/destinationTokens', destinationTokensRoute)
 
 export default router

packages/rest-api/src/tests/destinationTokensRoute.test.ts

@@ -0,0 +1,99 @@
+import request from 'supertest'
+import express from 'express'
+
+import destinationTokensRoute from '../routes/destinationTokensRoute'
+
+const app = express()
+app.use('/destinationTokens', destinationTokensRoute)
+
+describe('destinatonTokens Route', () => {
+  it('should return destination tokens for valid input', async () => {
+    const response = await request(app).get('/destinationTokens').query({
+      fromChain: '1',
+      fromToken: '0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48',
+    })
+
+    expect(response.status).toBe(200)
+    expect(Array.isArray(response.body)).toBe(true)
+    expect(response.body.length).toBeGreaterThan(0)
+    expect(response.body[0]).toHaveProperty('symbol')
+    expect(response.body[0]).toHaveProperty('address')
+    expect(response.body[0]).toHaveProperty('chainId')
+  })
+
+  it('should return 400 for unsupported fromChain', async () => {
+    const response = await request(app).get('/destinationTokens').query({
+      fromChain: '999',
+      fromToken: '0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48',
+    })
+
+    expect(response.status).toBe(400)
+    expect(response.body.error).toHaveProperty(
+      'message',
+      'Unsupported fromChain'
+    )
+  })
+
+  it('should return 400 for invalid fromToken address', async () => {
+    const response = await request(app).get('/destinationTokens').query({
+      fromChain: '1',
+      fromToken: 'invalid_address',
+    })
+
+    expect(response.status).toBe(400)
+    expect(response.body.error).toHaveProperty(
+      'message',
+      'Invalid fromToken address'
+    )
+  })
+
+  it('should return 400 for token not supported by Synapse', async () => {
+    const response = await request(app).get('/destinationTokens').query({
+      fromChain: '1',
+      fromToken: '0xC011a73ee8576Fb46F5E1c5751cA3B9Fe0af2a6F',
+    })
+
+    expect(response.status).toBe(400)
+    expect(response.body.error).toHaveProperty(
+      'message',
+      'Unsupported fromToken address'
+    )
+  })
+
+  it('should return 400 for token not supported on specified chain', async () => {
+    const response = await request(app).get('/destinationTokens').query({
+      fromChain: '10',
+      fromToken: '0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48',
+    })
+
+    expect(response.status).toBe(400)
+    expect(response.body.error).toHaveProperty(
+      'message',
+      'Token not supported on specified chain'
+    )
+  })
+
+  it('should return 400 for missing fromChain', async () => {
+    const response = await request(app).get('/destinationTokens').query({
+      fromToken: '0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48',
+    })
+
+    expect(response.status).toBe(400)
+    expect(response.body.error).toHaveProperty(
+      'message',
+      'fromChain is required'
+    )
+  })
+
+  it('should return 400 for missing fromToken', async () => {
+    const response = await request(app).get('/destinationTokens').query({
+      fromChain: '1',
+    })
+
+    expect(response.status).toBe(400)
+    expect(response.body.error).toHaveProperty(
+      'message',
+      'fromToken is required'
+    )
+  })
+})

packages/rest-api/src/utils/bridgeRouteMapping.ts

@@ -0,0 +1,67 @@
+import { EthAddress, ZeroAddress } from '../constants'
+import { BRIDGE_MAP } from '../constants/bridgeMap'
+
+interface TokenInfo {
+  symbol: string
+  address: string
+  chainId: string
+}
+
+interface BridgeRoutes {
+  [key: string]: TokenInfo[]
+}
+
+const constructJSON = (
+  swappableMap: typeof BRIDGE_MAP,
+  exclusionList: string[]
+): BridgeRoutes => {
+  const result: BridgeRoutes = {}
+
+  for (const chainA in swappableMap) {
+    for (const addressA in swappableMap[chainA]) {
+      const tokenA = swappableMap[chainA][addressA]
+      const keyA = `${tokenA.symbol}-${chainA}`
+
+      if (exclusionList.includes(keyA)) {
+        continue
+      }
+
+      result[keyA] = []
+
+      for (const chainB in swappableMap) {
+        if (chainA !== chainB) {
+          for (const addressB in swappableMap[chainB]) {
+            const tokenB = swappableMap[chainB][addressB]
+            const keyB = `${tokenB.symbol}-${chainB}`
+
+            if (exclusionList.includes(keyB)) {
+              continue
+            }
+
+            const canBridge = tokenA.origin.some(
+              (bridgeSymbol) =>
+                tokenB.destination.includes(bridgeSymbol) ||
+                tokenB.origin.includes(bridgeSymbol)
+            )
+
+            if (canBridge) {
+              result[keyA].push({
+                symbol: tokenB.symbol,
+                address: addressB === EthAddress ? ZeroAddress : addressB,
+                chainId: chainB,
+              })
+            }
+          }
+        }
+      }
+
+      if (result[keyA].length === 0) {
+        delete result[keyA]
+      }
+    }
+  }
+
+  return result
+}
+
+export const BRIDGE_ROUTE_MAPPING: BridgeRoutes = constructJSON(BRIDGE_MAP, [])

packages/rest-api/src/utils/tokenAddressToToken.ts

@@ -1,11 +1,15 @@
+import { EthAddress, ZeroAddress } from '../constants'
 import { BRIDGE_MAP } from '../constants/bridgeMap'
 
 export const tokenAddressToToken = (chain: string, tokenAddress: string) => {
   const chainData = BRIDGE_MAP[chain]
   if (!chainData) {
     return null
   }
-  const tokenInfo = chainData[tokenAddress]
+
+  const address = tokenAddress === ZeroAddress ? EthAddress : tokenAddress
+
+  const tokenInfo = chainData[address]
   if (!tokenInfo) {
     return null
   }