cmd.js

#!/usr/bin/env node

/**
 * Module dependencies.
 */

var program = require("commander");
var fs = require("fs");
var path = require("path");
var pkg = JSON.parse(
  fs.readFileSync(path.join(__dirname, "..", "package.json"))
);
var build = require("../lib/build");
var serve = require("../lib/serve");

program.version(pkg.version);

const stringBooleanToBoolean = val => {
  console.log({val});
  if (typeof val !== 'string' && (val !== 'true' || val !== 'false')) {
    throw Error(`Incorrect string value: ${val}`);
  }

  return val === 'true';
};

program
  .option("-c --config <webpack-config>", "additional webpack configuration")
  .option("-p --port <port>", "port to serve from (default: 9000)")
  .option("-b --babelrc <babelrc>", "use .babelrc in root (default: true)", stringBooleanToBoolean)
  .option(
    "-t --timeout <timeout>",
    "function invocation timeout in seconds (default: 10)"
  )
  .option("-s --static", "serve pre-built lambda files");

program
  .command("serve <dir>")
  .description("serve and watch functions")
  .action(function(cmd, options) {
    console.log("netlify-lambda: Starting server");
    var static = Boolean(program.static);
    var server;
    var startServer = function() {
      server = serve.listen(
        program.port || 9000,
        static,
        Number(program.timeout) || 10
      );
    }
    if (static) {
      startServer();
      return; // early terminate, don't build
    };
  
    const { config: userWebpackConfig, babelrc: useBabelrc = true} = program;
    build.watch(cmd, {userWebpackConfig, useBabelrc}, function(err, stats) {
      if (err) {
        console.error(err);
        return;
      }

      console.log(stats.toString({ color: true }));
      if (!server) {
        startServer();
      }
      stats.compilation.chunks.forEach(function(chunk) {
        server.clearCache(chunk.name || chunk.id.toString());
      });
    });
  });

program
  .command("build <dir>")
  .description("build functions")
  .action(function(cmd, options) {
    console.log("netlify-lambda: Building functions");

    const { config: userWebpackConfig, babelrc: useBabelrc = true} = program;
    build
      .run(cmd, { userWebpackConfig, useBabelrc})
      .then(function(stats) {
        console.log(stats.toString({ color: true }));
      })
      .catch(function(err) {
        console.error(err);
        process.exit(1);
      });
  });

// error on unknown commands
// ref: https://github.com/tj/commander.js#custom-event-listeners
program.on("command:*", function() {
  console.error(
    "Invalid command: %s\nSee --help for a list of available commands.",
    program.args.join(" ")
  );
  process.exit(1);
});

program.parse(process.argv);

// check if no command line args are provided
// ref: https://github.com/tj/commander.js/issues/7#issuecomment-32448653
var NO_COMMAND_SPECIFIED = program.args.length === 0;

if (NO_COMMAND_SPECIFIED) {
  // user did not supply args, so show --help
  program.help();
}