Javascript Regular Expressions convert String to int

function filterInt(value) {
  if (/^[-+]?(\d+|Infinity)$/.test(value)) {
    return Number(value)
  } else {//from  w w w.  j ava  2  s.c  o m
    return NaN
  }
}

console.log(filterInt('42'));
console.log(filterInt('-42'));
console.log(filterInt('+42'));
console.log(filterInt('Infinity'));
console.log(filterInt('1.618'));
console.log(filterInt('1.ASDF'));
console.log(filterInt('ASDF.618'));
console.log(filterInt('1E10'));
console.log(filterInt('1n'));