Visual studio code - keyboard shortcuts - expand/collapse all

Here it is.

Ctrl+Shift+[    Fold (collapse) region  editor.fold
Ctrl+Shift+]    Unfold (uncollapse) region  editor.unfold
Ctrl+K Ctrl+[   Fold (collapse) all subregions  editor.foldRecursively
Ctrl+K Ctrl+]   Unfold (uncollapse) all subregions  editor.unfoldRecursively
Ctrl+K Ctrl+0   Fold (collapse) all regions editor.foldAll
Ctrl+K Ctrl+J   Unfold (uncollapse) all regions

Take Look at Visual studio Code Keybindings section at this link.

Also Platform specific Key board shortcuts available in pdf.here is the links

Windows,MAC,Linux

You can set custom values for that.

1. Open the Command Palette (⌘ + ⇧ + P or F1 on Mac)
2. Search Open Keyboard Shortcuts
3. Then search for collapse
4. Finally click the + sign near the Collapse All and Collapse Folders in Explorer options and set the shortcuts like I did

Or you can open keybindings.json file and add this to the main array.

 ,
  {
    "key": "cmd+k cmd+s",
    "command": "search.action.collapseSearchResults"
  },
  {
    "key": "cmd+k cmd+e",
    "command": "workbench.files.action.collapseExplorerFolders"
  }