calc.js

const example = "(2+2.0) *2"

const calculator = expr => {
    while ( expr.match(/\(/) ) {
        expr = expr.replace(/\(([^\)]+)\)/g, (_,subExpr) => calculator(subExpr))
    }

    while ( expr.match(/[\*\/]/) ) {
        expr = expr.replace(/([0-9\.]+)\s*([\*\/])\s*([0-9\.]+)/g, calculator.process)
    }

    while ( expr.match(/[\+\-]/) ) {
        expr = expr.replace(/([0-9\.]+)\s*([\+\-])\s*([0-9\.]+)/g, calculator.process)
    }

    return expr
}

calculator.process = (_, x, op, y) => {
    x = parseFloat(x)
    y = parseFloat(y)

    switch (op) {
        case "+": return x + y
        case "-": return x - y
        case "*": return x * y
        case "/": return x / y
        default: return NaN
    }
}

console.log(calculator(example))