code: function DocumentRemove(properties) {
                      this.removedTargetIds = [];
                      if (properties)
                          for (var keys = Object.keys(properties), i = 0; i < keys.length; ++i)
                              if (properties[keys[i]] != null)
                                  this[keys[i]] = properties[keys[i]];
                  }
docs: Properties of a DocumentRemove.
  @memberof google.firestore.v1
  @interface IDocumentRemove
  @property {string|null} [document] DocumentRemove document
  @property {Array.<number>|null} [removedTargetIds] DocumentRemove removedTargetIds
  @property {google.protobuf.ITimestamp|null} [readTime] DocumentRemove readTime
   
  Constructs a new DocumentRemove.
  @memberof google.firestore.v1
  @classdesc Represents a DocumentRemove.
  @implements IDocumentRemove
  @constructor
  @param {google.firestore.v1.IDocumentRemove=} [properties] Properties to set