file.js

import { exec, spawn } from 'child_process';

const args = process.argv;

// If false, it fails with the following error:
// 1 | import { exec, spawn } from 'child_process';
// 2 | 
// 3 | const args = process.argv;
// 4 | 
// 5 | if (args.length < 4) {
// 6 |   fail("Too few arguments are provided");
//       ^
// ReferenceError: Cannot access uninitialized variable.
//       at /Users/vadim/Workspace/game/build.js:6:3

// if true, works normally 🤔
if (args.length < 4) {
  fail("Too few arguments are provided");
}

build({
  "client": {
    "compile": [ Client.compile ],
    "run": [ Client.compile, Client.run ]
  },
});

async function build(data) {
  const target = data[args[2]];
  if (!target) fail(`Unsupported target '${args[2]}'`);

  const operation = target[args[3]];
  if (!operation) fail(`Unsupported operation '${args[3]}'`);

  for (const stage of operation) {
    await stage();
  }
  console.log("\n👍 Build completed");
}

const Client = {
  async compile() {
    console.log("Compiling the client");
    await compile("client");
    await bundle("client", args[4]);
  },

  async run() {
    console.log("Running the client locally");
    const { error, stdout, stderr } = await runLive("client", "bun http-server . -c-1");
    if (error) fail(`Failed to run the client locally: ${error}`);
  }
}

async function compile(project) {
  const { error, stdout, stderr } = await run(project, "rm -rf build && bunx tsc");
  if (error) fail(`Failed to compile the project '${project}': ${error}`);
}

async function bundle(project, mode="development") {
    const { error, stdout, stderr } = await run(project, `bunx webpack --mode=${mode}`);
    if (error) fail(`Failed to bundle the project '${project}': ${error}`);
}

function run(dir, cmd) {
  console.log(`Executing '${cmd}' in the directory '${dir}'`)
  return new Promise((resolve, reject) => {
    exec(`${cmd}`, { cwd: dir }, (error, stdout, stderr) => {
      resolve({error, stdout, stderr});
    });
  });
}

function runLive(dir, cmd) {
  const promise = new Promise((resolve, reject) => {
    console.log(`Executing '${cmd}' in the directoy '${dir}'`)
    const process = spawn(cmd, { shell: true, cwd: dir });
    process.stdout.setEncoding("utf-8");
    process.stdout.on('data', (d) => console.log(d));
    process.stderr.setEncoding("utf-8");
    process.stderr.on('data', (d) => console.log(d));
    process.on('close', () => resolve());
  });
  return promise;
}

function fail(message) {
  console.error(message);
  process.exit(1);
}