prevent nodeJS warnings in production

this change:
- configures ESbuild to rewrite "process.env.NODE_ENV" as "production"
  during build.
- configures the CLI to remove warning event listeners (which include
  the built-in event listener that logs to stderr on warning) when run
  in production env.

package.json

@@ -70,7 +70,7 @@
     "pretest:ci": "npm run build:app",
     "test:ci": "mocha --recursive ./test --require ./test/mocha-root-hooks.mjs --reporter mocha-multi-reporters --reporter-options configFile=./test/config/reporter.json",
     "build": "npm run build:app && npm run build:sea",
-    "build:app": "esbuild --bundle ./src/user-entrypoint.mjs --platform=node --outfile=./dist/cli.cjs --format=cjs --inject:./sea/import-meta-url.js --define:import.meta.url=importMetaUrl",
+    "build:app": "esbuild --bundle ./src/user-entrypoint.mjs --platform=node --outfile=./dist/cli.cjs --format=cjs --inject:./sea/import-meta-url.js --define:import.meta.url=importMetaUrl --define:process.env.NODE_ENV=\\\"production\\\"",
     "build:sea": "node ./sea/build.cjs",
     "format": "prettier -w ."
   },

src/cli.mjs

@@ -27,6 +27,9 @@ export async function run(argvInput, _container) {
   container = _container;
   const logger = container.resolve("logger");
   const parseYargs = container.resolve("parseYargs");
+  if (process.env.NODE_ENV === "production") {
+    process.removeAllListeners("warning");
+  }
 
   try {
     builtYargs = buildYargs(argvInput);
@@ -83,6 +86,12 @@ function buildYargs(argvInput) {
       },
       builder: {},
     })
+    .command("warn", false, {
+      handler: async () => {
+        process.emitWarning("this is a warning emited on the node process");
+      },
+      builder: {},
+    })
     .demandCommand()
     .strict(true)
     .options({

test/general-cli.mjs

@@ -1,5 +1,6 @@
 //@ts-check
 
+import { spawnSync } from "node:child_process";
 import * as fs from "node:fs";
 import path from "node:path";
 import { fileURLToPath } from "node:url";
@@ -13,6 +14,8 @@ import { builtYargs, run } from "../src/cli.mjs";
 import { setupTestContainer as setupContainer } from "../src/config/setup-test-container.mjs";
 import { f } from "./helpers.mjs";
 
+const __dirname = import.meta.dirname;
+
 describe("cli operations", function () {
   let container;
 
@@ -124,6 +127,40 @@ describe("cli operations", function () {
     expect(notify).to.have.been.called;
   });
 
+  it("enables nodeJS warnings from the dev entrypoint", async function () {
+    const cliPath = path.resolve(__dirname, "../src/user-entrypoint.mjs");
+    let cli = spawnSync(cliPath, ["warn"], {
+      encoding: "utf8",
+      // input: "",
+      timeout: 5000,
+      // stdio: ["inherit", "pipe", "pipe"],
+      // shell: true,
+    });
+    if (cli.error) throw cli.error;
+    let stderr = cli.stderr;
+
+    // the dev script should emit warnings
+    expect(stderr).to.include(
+      "Warning: this is a warning emited on the node process",
+    );
+  });
+
+  it("suppresses nodeJS warnings from the prod entrypoint", async function () {
+    const cliPath = path.resolve(__dirname, "../dist/cli.cjs");
+    let cli = spawnSync(cliPath, ["warn"], {
+      encoding: "utf8",
+      // input: "",
+      timeout: 5000,
+      // stdio: ["inherit", "pipe", "pipe"],
+      // shell: true,
+    });
+    if (cli.error) throw cli.error;
+
+    let stderr = cli.stderr;
+    // the prod one should not
+    expect(stderr).to.equal("");
+  });
+
   it.skip("should detect color support if the user does not specify", async function () {
     // i can't find a way to mock this that doesn't involve setting a flag
     // and setting a flag defeats the purpose of testing if it's _detected_ automatically