040000 tree 97ff8a65508d252f24947432ef29668b0753ab2d	commands
100644 blob babe0420123b103ddbd9e007b0d694d6ae6d18a4	undo-redo-stack.component.ts
100644 blob 25d8fe08396b7bfd0cad3517cf4817f7a1471e13	undo-redo-stack.module.ts
100644 blob a23f3a8b120081ae7b6119d3aa2e5effd9057438	undo-redo-stack.spec.ts