feat: generate keypair and add to .env if one doesn't exist

.gitignore

@@ -1,2 +1,3 @@
 src/temp
 dist
+node_modules

package.json

@@ -21,6 +21,7 @@
   "dependencies": {
     "@digitak/esrun": "^3.2.24",
     "bs58": "^5.0.0",
+    "dotenv": "^16.3.1",
     "prettier": "^3.0.3",
     "typescript": "^5.2.2"
   },

src/index.test.ts

@@ -1,12 +1,16 @@
-import { describe, test, before } from "node:test";
+import { before, describe, test } from "node:test";
+import { getKeypairFromEnvironment, getKeypairFromFile } from "./index";
+
+import { Keypair } from "@solana/web3.js";
 import assert from "node:assert/strict";
-import { promisify } from "util";
+import base58 from "bs58";
+import dotenv from "dotenv";
 import { exec as execForOldPeople } from "child_process";
-const exec = promisify(execForOldPeople);
-import { Keypair } from "@solana/web3.js";
-import { getKeypairFromFile, getKeypairFromEnvironment } from "./index";
+import { promisify } from "util";
+import { unlinkSync } from "node:fs";
 import { writeFile } from "node:fs/promises";
-import base58 from "bs58";
+
+const exec = promisify(execForOldPeople);
 
 const log = console.log;
 
@@ -68,10 +72,24 @@ describe("getKeypairFromEnvironment", () => {
     await getKeypairFromEnvironment(TEST_ENV_VAR_BASE58);
   });
 
-  test("throws a nice error if the env var doesn't exist", async () => {
-    assert.rejects(async () => getKeypairFromEnvironment("MISSING_ENV_VAR"), {
-      message: `Please set 'MISSING_ENV_VAR' in environment.`,
-    });
+  test("generates new keypair and writes to env if variable doesn't exist", async () => {
+    // Returns a new keypair and writes it to the .env file
+    const newKeypair = await getKeypairFromEnvironment("MISSING_ENV_VAR");
+    // Load the .env file
+    dotenv.config();
+    // Get the secret from the .env file
+    const secretKeyString = process.env["MISSING_ENV_VAR"];
+
+    if (!secretKeyString) {
+      throw new Error("MISSING_ENV_VAR not found in environment");
+    }
+    const decodedSecretKey = Uint8Array.from(JSON.parse(secretKeyString));
+    const envKeypair = Keypair.fromSecretKey(decodedSecretKey);
+
+    assert.deepStrictEqual(newKeypair.secretKey, envKeypair.secretKey);
+
+    // delete the .env file
+    unlinkSync(".env");
   });
 
   test("throws a nice error if the value of the env var isn't valid", async () => {

src/index.ts

@@ -1,7 +1,8 @@
 import { Keypair } from "@solana/web3.js";
-import { readFile } from "fs/promises";
 import base58 from "bs58";
+import fs from "fs";
 import path from "path";
+import { readFile } from "fs/promises";
 const log = console.log;
 
 // Default value from Solana CLI
@@ -45,7 +46,13 @@ export const getKeypairFromFile = async (filepath?: string) => {
 export const getKeypairFromEnvironment = (variableName: string) => {
   const secretKeyString = process.env[variableName];
   if (!secretKeyString) {
-    throw new Error(`Please set '${variableName}' in environment.`);
+    // Generate a new keypair if one doesn't exist and add it to a `.env` file
+    const keypair = Keypair.generate();
+    fs.appendFileSync(
+      ".env",
+      `\n${variableName}=${JSON.stringify(Array.from(keypair.secretKey))}`,
+    );
+    return keypair;
   }
 
   // Try the shorter base58 format first