Restarting

The jj restore --help page states:

When neither --from nor --into is specified, the command restores into the working copy from its parent(s).

That's a neat default! It means that:

jj restore

is equivalent to:

jj restore -f @- -t @ .

which makes the Current Change identical to its parent. It's a convenient way to clean up everything and start over.

Give it a try:

○  rt           Link to CSS
○  n            Square is interactive
○    ru         Board() invokes Square()
├─╮
○ │  ym         Rename: Square -> Board
○ │  xx         WIP delete me
○ │  yz         LICENSE
○ │  ws         A board full of X
├─╯
○  kk           Displays X X
○  wx           Fails
○  rx           Scaffold application

Select any Change you like (say: ru) and create a new Change on top of it:

jj new ru

Make any modification you like:

$ touch unnecessary.txt
$ echo "a bug" >> src/App.js
$ rm src/index.js

$ jj st
Working copy changes:
M public/index.html
M src/App.js
D src/index.js
A unnecessary.txt

2 modified files, 1 deleted and 1 added.
How to start over and get back to an empty Change?

$ jj restore
Added 1 files, modified 2 files, removed 1 files

$ jj st
The working copy has no changes.

Back to the start.

Isn't This equivalent to git restore?

Not really. In Git, the same information is spread across three layers, HEAD, the Index, and the working tree, plus the fourth grey area of untracked files. As a result, you need different commands and options depending on which subset you want to affect.