How to remove a character at the end of a string if there is one?

Question

JavaScript

There is this line: string:string:.
Or like this: string:string.

The string must always be in the format string:string, i.e. without :at the end.

Answer 1

str.replace(/:$/, '')

Answer 2

let str = "string:string:";
let res = str.slice(0, -1);
alert(res);

JsFiddle