How to support percentage/suffix

[jzhu-24]

Hey all! Anyone know how to support percentage/suffix? aka always showing a character like % whenever there's input regardless of length? The closest I got was this, but I feel like there could be a simpler way I'm missing:

          mask: [
            { mask: "0%" },
            {
              mask: "#0%",
              definitions: {
                "#": /[1-9]/
              }
            },
            {
              mask: "#00%",
              definitions: {
                "#": /[1]/
              }
            }
          ],
          prepare: (value) => value + "a", // hack to show % after del or weird input
          eager: true