Simple example of a command REPL in Node.js

command-repl.js

const readline = require("readline");

let input = readline.createInterface({
  input: process.stdin,
  output: process.stdout
});

let queryCommand = () => {
  input.question("Command: ", (command) => {
    if (command === "exit") {
      input.close();
    } else {
      commandHandler(command);
      queryCommand();
    }
  });
};

let commandHandler = (command) => {
  // TODO: Replace with custom command handling
  console.info("User entered: " + command);
};

queryCommand();