phpjs/functions/math/is_finite.js

php.js offers community built php functions in javascript

function is_finite(val) {
  //  discuss at: http://phpjs.org/functions/is_finite/
  // original by: Onno Marsman
  //   example 1: is_finite(Infinity);
  //   returns 1: false
  //   example 2: is_finite(-Infinity);
  //   returns 2: false
  //   example 3: is_finite(0);
  //   returns 3: true

  var warningType = '';

  if (val === Infinity || val === -Infinity) {
    return false;
  }

  //Some warnings for maximum PHP compatibility
  if (typeof val === 'object') {
    warningType = (Object.prototype.toString.call(val) === '[object Array]' ? 'array' : 'object');
  } else if (typeof val === 'string' && !val.match(/^[\+\-]?\d/)) {
    //simulate PHP's behaviour: '-9a' doesn't give a warning, but 'a9' does.
    warningType = 'string';
  }
  if (warningType) {
    throw new Error('Warning: is_finite() expects parameter 1 to be double, ' + warningType + ' given');
  }

  return true;
}