How to replace a variable in a snippet in Visual Studio Code?

I use javascript snippet with keybinding.

I have this code below:

    {
        "key": "alt+c", 
        "command": "editor.action.insertSnippet",
        "when": "editorTextFocus",
        "args": {
            "snippet": " const $TM_CURRENT_WORD = $1"
        }
    },

If I type box and than press alt+c, I get...

box const box = 

But I expected

const box =

How can I achieve that?