initial ws server with lookupToken

token.js

@@ -0,0 +1,36 @@
+// keeps a list of known tokens
+
+// todo load standard known tokens
+
+import {ethers} from "ethers";
+import {erc20Abi} from "./abi.js";
+import {provider} from "./blockchain.js";
+
+const tokens = {
+    42161: {}
+}
+
+export async function lookupToken(chainId, address) {
+    console.log('lookupToken', chainId, address)
+    const chainTokens = tokens[chainId]
+    if( chainTokens === undefined )
+        return null
+    try {
+        let result = chainTokens[address]
+        console.log('found', result)
+        if (result === undefined) {
+            // todo look in tokens project
+            const addr = ethers.getAddress(address)
+            console.log('addr', addr)
+            const token = new ethers.Contract(addr, erc20Abi, provider(chainId))
+            const symbol = await token.symbol()
+            console.log('symbol', symbol)
+            const decimals = Number(await token.decimals())
+            result = {name: `${symbol} (${addr})`, symbol, decimals, address: addr}
+            chainTokens[addr] = result
+            return result
+        }
+    } catch {
+        return null
+    }
+}