How can I display “-” as long as string length in textbox?

I have this list:

let teams = [
“real madrid”,
“barcelona”,
“milan”,
“inter”,
“juventus”,
“manchester united”,
“manchester city”,
“liverpool”,
“arsenal”,
“chelsea”,
“bayern munich”,
];

I wrote code for choose random item from this list but I want display “-” as long as item length.

For example: choose real madrid … I want this – – – – – – – – – – in the text box.