sh.js

let childProcess = require('child_process');

function createHandler(commands) {
  return new Proxy(function() {}, {
    get(target, property) {
      return createHandler(commands.concat(property));
    },
    apply(target, context, args) {
      return new Promise((resolve, reject) => {
        let command = commands.concat(args).join(' ');
        childProcess.exec(command, { cwd: process.cwd() }, (error, stdout) => {
          if (error) {
            reject(error);
          } else {
            resolve(stdout);
          }
        });
      });
    }
  });
}

module.exports = createHandler([]);