add ethereum erc-20 balance chnages example

examples/ethereum-erc20-balance-changes.mjs

@@ -0,0 +1,69 @@
+import { createModuleHashHex, createRegistry, createRequest } from "@substreams/core";
+import { readPackage } from "@substreams/manifest";
+import { BlockEmitter, createNodeTransport } from "@substreams/node";
+
+// auth API token
+// https://app.streamingfast.io/
+// https://app.pinax.network/
+if (!process.env.SUBSTREAMS_API_TOKEN) {
+  throw new Error("SUBSTREAMS_API_TOKEN is require");
+}
+
+const token = process.env.SUBSTREAMS_API_TOKEN;
+const baseUrl = "https://eth.substreams.pinax.network:443";
+
+// User parameters
+const manifest = "https://github.com/pinax-network/substreams-erc20-balance-changes/releases/download/v1.2.0/erc20-balance-changes-mainnet-v1.2.0.spkg";
+const outputModule = "map_balance_changes";
+const startBlockNum = -1000;
+
+// Read Substream
+const substreamPackage = await readPackage(manifest);
+if (!substreamPackage.modules) {
+  throw new Error("No modules found in substream package");
+}
+const moduleHash = await createModuleHashHex(substreamPackage.modules, outputModule);
+console.log({ moduleHash });
+
+// Connect Transport
+const headers = new Headers({ "User-Agent": "@substreams/node" });
+const registry = createRegistry(substreamPackage);
+const transport = createNodeTransport(baseUrl, token, registry, headers);
+const request = createRequest({
+  substreamPackage,
+  outputModule,
+  startBlockNum,
+});
+
+// NodeJS Events
+const emitter = new BlockEmitter(transport, request, registry);
+
+// Session Trace ID
+emitter.on("session", (session) => {
+  console.dir(session);
+});
+
+// Stream Blocks
+emitter.on("anyMessage", (message, cursor, clock) => {
+  for ( const balanceChange of message.balanceChanges ?? []) {
+    console.dir(balanceChange);
+  }
+  console.dir({cursor, ...clock});
+});
+
+// End of Stream
+emitter.on("close", (error) => {
+  if (error) {
+    console.error(error);
+  }
+  console.timeEnd("🆗 close");
+});
+
+// Fatal Error
+emitter.on("fatalError", (error) => {
+  console.error(error);
+});
+
+console.log("✅ start");
+console.time("🆗 close");
+emitter.start();