fix(router-sdk): isValidTokenPath should not cast currency to token f…

…or v4 pool (#283)

sdks/router-sdk/src/index.ts

@@ -12,3 +12,4 @@ export * from './utils/encodeMixedRouteToPath'
 export * from './utils/TPool'
 export * from './utils/pathCurrency'
 export * from './utils'
+export * from './utils/isValidTokenPath'

sdks/router-sdk/src/utils/isValidTokenPath.test.ts

@@ -0,0 +1,19 @@
+import { Ether, Token, WETH9 } from '@uniswap/sdk-core'
+import { FeeAmount, encodeSqrtRatioX96 } from '@uniswap/v3-sdk'
+import { Pool as V4Pool } from '@uniswap/v4-sdk'
+import { ADDRESS_ZERO } from '../constants'
+import { isValidTokenPath } from './isValidTokenPath'
+
+describe('#isValidTokenPath', () => {
+  const SQRT_RATIO_ONE = encodeSqrtRatioX96(1, 1)
+  const ETHER = Ether.onChain(1)
+  const token1 = new Token(1, '0x0000000000000000000000000000000000000002', 18, 't1')
+  const weth = WETH9[1]
+
+  const pool_v4_weth_eth = new V4Pool(weth, ETHER, 0, 0, ADDRESS_ZERO, 79228162514264337593543950336, 0, 0)
+  const pool_v4_1_eth = new V4Pool(token1, ETHER, FeeAmount.MEDIUM, 60, ADDRESS_ZERO, SQRT_RATIO_ONE, 0, 0)
+
+  it('v3 pool and v4 pool, with WETH and ETH unwrap', () => {
+    expect(isValidTokenPath(pool_v4_weth_eth, pool_v4_1_eth, ETHER)).toBe(true)
+  })
+})

sdks/router-sdk/src/utils/isValidTokenPath.ts

@@ -3,7 +3,9 @@ import { Pool as V4Pool } from '@uniswap/v4-sdk'
 import { TPool } from './TPool'
 
 export function isValidTokenPath(prevPool: TPool, currentPool: TPool, inputToken: Currency): boolean {
-  if (currentPool.involvesToken(inputToken as Token)) return true
+  if (inputToken instanceof Token && currentPool.involvesToken(inputToken)) return true
+
+  if (currentPool instanceof V4Pool && currentPool.involvesToken(inputToken)) return true
 
   // throw if both v4 pools, native/wrapped tokens not interchangeable in v4
   if (prevPool instanceof V4Pool && currentPool instanceof V4Pool) return false