feat(lazer): add js example

Author: Riateche

lazer/js/.gitignore

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+tsconfig.tsbuildinfo

lazer/js/package-lock.json

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+{
+  "name": "pyth-lazer-js-example",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "type": "module",
+  "scripts": {
+    "start": "node --loader ts-node/esm src/index.js",
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "author": "",
+  "license": "Apache-2.0",
+  "dependencies": {
+    "@pythnetwork/pyth-lazer-sdk": "^0.1.1"
+  },
+  "devDependencies": {
+    "@cprussin/tsconfig": "^3.0.1",
+    "ts-node": "^10.9.2",
+    "typescript": "^5.7.2"
+  }
+}

lazer/js/package.json

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+import { PythLazerClient } from "@pythnetwork/pyth-lazer-sdk";
+
+/* eslint-disable no-console */
+const client = new PythLazerClient("wss://pyth-lazer-staging.dourolabs.app/v1/stream", "my_token");
+client.addMessageListener((message) => {
+  console.log("got message:", message);
+  switch (message.type) {
+    case "json": {
+      if (message.value.type == "streamUpdated") {
+        console.log(
+          "stream updated for subscription",
+          message.value.subscriptionId,
+          ":",
+          message.value.parsed?.priceFeeds
+        );
+      }
+      break;
+    }
+    case "binary": {
+      if ("solana" in message.value) {
+        console.log("solana message:", message.value.solana?.toString("hex"));
+      }
+      if ("evm" in message.value) {
+        console.log("evm message:", message.value.evm?.toString("hex"));
+      }
+      break;
+    }
+  }
+});
+client.ws.addEventListener("open", () => {
+  client.send({
+    type: "subscribe",
+    subscriptionId: 1,
+    priceFeedIds: [1, 2],
+    properties: ["price"],
+    chains: ["solana"],
+    deliveryFormat: "json",
+    channel: "fixed_rate@200ms",
+    jsonBinaryEncoding: "hex",
+  });
+});

lazer/js/src/index.ts

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+{
+  "extends": "@cprussin/tsconfig/base.json",
+  "exclude": [
+    "node_modules",
+    "dist"
+  ]
+}