In VSCode, Exit "insert" mode (when using vim plugin) via keybinding

Question

I want to create a key binding that when I press 'f+j' key (f AND k) keys when I am in "insert" mode, exit to visual mode.

I tried this on the keybinding.json but did not work:

{ "key": "fj",
 "command": "extension.vim_escape",
    "when": "editorTextFocus && vim.active && !inDebugRepl" },
}