message: tweak HashMap.
diff: @@ -588,9 +588,15 @@ export function isPrimitive(obj) {
  */
  function HashMap(obj) {
  var isArr = isArray(obj);
  - obj && each(obj, function (value, key) {
  - isArr ? this.set(value, key) : this.set(key, value);
  - }, this);
  + var thisMap = this;
  +
  + (obj instanceof HashMap)
  + ? obj.each(visit)
  + : (obj && each(obj, visit));
  +
  + function visit(value, key) {
  + isArr ? thisMap.set(value, key) : thisMap.set(key, value);
  + }
  }
  // Add prefix to avoid conflict with Object.prototype.
  