const Conf = require('conf');

const schema = {
  fizz: {
    type: 'string',
    default: 'buzz',
  },
  foo: {
    type: 'object',
    properties: {
      bar: {
        type: 'string',
        default: 'baz',
      },
    },
  },
};

const config = new Conf({schema});

console.log(config.get('fizz'));    // undefined - should be 'buzz'
console.log(config.get('foo'));     // undefined - should be { bar: 'baz' }
console.log(config.get('foo.bar')); // undefined - should be 'baz'

console.assert(config.get('fizz') === 'buzz');   // Assertion failed
console.assert(config.get('foo.bar') === 'baz'); // Assertion failed

function setDefaults(schema, config, key_chain) {
  for (let [key, val] of Object.entries(schema)) {
    let this_key = (key_chain ? key_chain + '.' : '') + key;
    if (val.type === 'object') {
      return setDefaults(val.properties, config, this_key);
    }
    if (!config.has(key) && Object.hasOwnProperty.call(val, 'default')) {
      config.set(this_key, val.default);
    }
  }
}