JSFiddle - React, Tailwind, and code Playground

JavaScript

var arr = [
    "10Regular", "18Regular", "14Long", "14Regular",
    "10Long", "16Long", "12Long", "20Regular",
    "16Regular", "12Regular", "18Long"
];

var trimmedAndSorted = arr.map(function(e) {
    return e.replace(/(\d+\w).*/, '$1');
}).sort();

alert(trimmedAndSorted);