Number.isFinite()

The Number.isFinite() method determines whether the passed value is a finite number — that is, it checks that the type of a given value is Number, and the number is neither positive Infinity, negative Infinity, nor NaN.

Number.isFinite(value)

value

The value to be tested for finiteness.

A Boolean indicating whether or not the given value is a finite number.

In comparison to the global isFinite() function, this method doesn't first convert the parameter to a number. This means only values of the type number and are finite return true.

Number.isFinite(Infinity);  // false
Number.isFinite(NaN);       // false
Number.isFinite(-Infinity); // false

Number.isFinite(0);         // true
Number.isFinite(2e64);      // true

Number.isFinite('0');       // false, would've been true with
                            // global isFinite('0')
Number.isFinite(null);      // false, would've been true with
                            // global isFinite(null)

if (Number.isFinite === undefined) Number.isFinite = function(value) {
    return typeof value === 'number' && isFinite(value);
}

• The Number object it belongs to.
• The global function isFinite.