price subscriptions

src/blockchain/uniswap.js

@@ -0,0 +1,24 @@
+import {ethers} from "ethers";
+
+const UNISWAPV3_POOL_INIT_CODE_HASH = '0xe34f199b19b2b4f47f68442619d555527d244f78a3297ea89325f843f87b8b54'
+const uniswapV3Addresses = {
+    42161: {
+        factory: '0x1F98431c8aD98523631AE4a59f267346ea31F984',
+    },
+    31337: {
+        factory: '0x1F98431c8aD98523631AE4a59f267346ea31F984',
+    },
+}
+
+export function uniswapV3PoolAddress(chainId, tokenAddrA, tokenAddrB, fee) {
+    const [addr0, addr1] = tokenAddrA < tokenAddrB ? [tokenAddrA, tokenAddrB] : [tokenAddrB, tokenAddrA]
+    const encoded = ethers.AbiCoder.defaultAbiCoder().encode(['address', 'address', 'uint24'], [addr0, addr1, fee]);
+    const salt = ethers.keccak256(encoded)
+    const factory = uniswapV3Addresses[chainId]?.factory
+    console.log('uni3addr', addr0, addr1, fee, salt, factory)
+    if (!factory) {
+        console.log('no uniswap factory for chain', chainId)
+        return null
+    }
+    return ethers.getCreate2Address(factory, salt, UNISWAPV3_POOL_INIT_CODE_HASH)
+}