lib/types.js
function MapType(attrs, opts) {
  Type.call(this);

  if (!attrs.values) {
    throw new Error(f('missing map values: %j', attrs));
  }
  this._values = createType(attrs.values, opts);

  // Addition by Edwin Elia
  var keys = attrs.keys;
  if (!keys) {
    keys = 'string';
  }
  this._keys = createType(keys, opts);
}
function MapType(attrs, opts) {
  Type.call(this);

  if (!attrs.values) {
    throw new Error(f('missing map values: %j', attrs));
  }
  this._values = createType(attrs.values, opts);

  // Addition by Edwin Elia
  var keys = attrs.keys;
  if (!keys) {
    keys = 'string';
  }
  this._keys = createType(keys, opts);
}
function MapType ( attrs , opts ) { Type . call ( this ) ; if ( ! attrs . values ) { throw new Error ( f ( 'missing map values: %j' , attrs ) ) ; } this . _values = createType ( attrs . values , opts ) ; // Addition by Edwin Elia var keys = attrs . keys ; if ( ! keys ) { keys = 'string' ; } this . _keys = createType ( keys , opts ) ; }
Avro map.

Represented as vanilla objects.
Avro map .