只能输入正整数

function toInt(number) {
    return Infinity === number ? 0 : (number*1 || 0).toFixed(0)*1;
}
function toInt2(_val) {
    let val = `${_val}`
    val = val.replace(/[^\d]/g, '')
    return val
}
const a = 0001
const num1 = toInt(a)
const num2 = toInt2(a)
const num3 = toInt(toInt2(a))
console.log('num3: ', num3); // num3:  1