JavaScript - Object2YAML

object2yaml.js

function concat(firstText, secondText) {
  return firstText + secondText;
}

function escape(key) {
  if (key.match(/^[A-Za-z0-9\-\_]+$/))
    return key
  else
    return `"${key}"`
}

function yaml(object, indent) {
  indent = indent || ''
  return Object.keys(object)
    .map(
      key => {
        if (typeof object[key] === 'string' || object[key] instanceof String)
          return `${indent}${escape(key)}: ${object[key]}\n`;
        else
          return `${indent}${escape(key)}:\n` + yaml(object[key], indent + '  ');
      }
    )
    .reduce(concat)
}