How do I check if a number evaluates to infinity?

Question

I have a series of Javascript calculations that (only under IE) show Infinity depending on user choices.

How does one stop the word Infinity appearing and for example, show 0.0 instead?

Answer 1

if (result == Number.POSITIVE_INFINITY || result == Number.NEGATIVE_INFINITY) {     // ... } 

You could possibly use the isFinite function instead, depending on how you want to treat NaN. isFinite returns false if your number is POSITIVE_INFINITY, NEGATIVE_INFINITY or NaN.

if (isFinite(result)) {     // ... } 

Answer 2

In ES6, The Number.isFinite() method determines whether the passed value is a finite number.

Number.isFinite(Infinity);  // false Number.isFinite(NaN);       // false Number.isFinite(-Infinity); // false  Number.isFinite(0);         // true Number.isFinite(2e64);      // true