Doppelganger 1.3.1

Doppelganger 1.3.1

TestsTested
LangLanguage Obj-CObjective C
License MIT
ReleasedLast Release Apr 2015

Maintained by Sash Zats.



TL;DR;

bad ux good ux
Bad UX Good UX1

1: Slowed down intentionally to demonstrate the awesomeness

Problems it solves

  • Calculating mutations is too hard and you're just calling reloadData on your collection or table view?
  • Users, confused where did that row disappear?
  • Rows, jumping out of nowhere?
  • Lost scroll position?

Doppelganger is here to help!

Usage

NSArray *oldDataSource = self.dataSource;
self.dataSource = [self _updatedDataSource];
NSArray *diffs = [WMLArrayDiffUtility diffForCurrentArray:self.dataSource
                                            previousArray:oldDataSource];
[self.tableView wml_applyBatchChanges:diffs
                            inSection:0
                     withRowAnimation:UITableViewRowAnimationRight];

Implementation details

  • Currently, doppelganger supports only array of unique elements, e.g. if you have duplicated elements in your array, result is unpredictable.
  • If you are using custom classes, make sure that it implements correctly isEqual: and hash methods: http://nshipster.com/equality/
  • Sections are not handled intentionally. From our experience sections are harder to match using strict equality + hashing. However, if this is your case, feel free to use Doppelganger for sections, too.

TODOs

  • Improve on O(n2) when calculating moved elements.
  • Abstract API from NSArray.
  • Your issue / pull request.

Installation

Author

Sash Zats, [email protected]

License

Doppelganger is available under the MIT license. See the LICENSE file for more info.