Decorate class property with ensure default value, boolean can't be null.

DefaultValue.js

const DefaultValue = defaultValue =>
  function(target, key) {
    let _val = this[key];

    // delete old property
    if (delete this[key]) {
      Object.defineProperty(target, key, {
        get: function() {
          return !!_val ? _val : defaultValue;
        },
        set: function(newVal) {
          return (_val = newVal);
        },
        enumerable: true,
        configurable: true,
      });
    }
  };

module.exports.DefaultValue = DefaultValue;