CODEWITHSUNDEEP
javascript
Abhay Kumar
Abhay Kumar

Reputation: 421

Detect Number overflow in Javascript

Is there any builtin function in javascript which will notify, overflow of arithmetic operation on number data type? Like c# and Java have.

Upvotes: 3

Views: 3143

Answers (2)

Ömür Alçin
Ömür Alçin

Reputation: 707

Check from this site : isSafeInteger

var x = Number.MAX_SAFE_INTEGER + 1;
var y = Number.MAX_SAFE_INTEGER + 2;

    console.log(Number.MAX_SAFE_INTEGER);
    // expected output: 9007199254740991

    console.log(x);
    // expected output: 9007199254740992
    console.log(y);
    // expected output: 9007199254740992
    console.log(x === y);
    // expected output: true
    
function warn(a) {
  if (Number.isSafeInteger(a)) {
    return 'Precision safe.';
  }
  return 'Precision may be lost!';
}

    console.log(warn(Number.MAX_SAFE_INTEGER));
    // expected output: "Precision safe."

    console.log(warn(x));
    // expected output: "Precision may be lost!"
    console.log(warn(y)); 
    // expected output: "Precision may be lost!"

Upvotes: 5

Jonas Wilms
Jonas Wilms

Reputation: 138307

Unlike the languages you were referencing, JavaScript does not throw if an invalid math operation is done. Instead, it returns special number values to notify you (doing Math on them always results in that specific value again, so you can just check for them at the end of an arithmetic chain):

 NaN // Operation could not be done
 Infinity // Number was too large
 -Infinity // Number was too small

For all those three special cases you can use isFinite to check against:

 // a = 1000, b = 1000, c = 1 -> Infinity
 // a = -1000, b = 1001, c = 1 -> -Infinity
 const a = 2, b = 51, c = 0; // divide by zero -> NaN
 const result = a ** b / c;
 if(!isFinite(result)) {
   console.log("invalid operation");
 }

Also be aware that JavaScript numbers are floating point, with a precise integer range between (-2 ** 53, 2 ** 53), every integer outside of that will lose accuracy. The same applies to any non integer arithmetic which is never accurate.

Upvotes: 2

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