JSFiddle - React, Tailwind, and code Playground

by Nickolay Ilchenko

JavaScript

while (true) {
    var number = prompt('Enter math expression', '2-');
    try {
        var result = eval(number);

        if (isNaN(result)) {
            throw new Error('Enter correct expression');
        }
        
        break;
        
    } catch (err) {
        alert('Имя ошибки: ' + err.name);
    }
}

alert(result);