This question already has answers here:
Large numbers erroneously rounded in JavaScript
(6 answers)
Javascript parseInt() with leading zeros
(7 answers)
Closed 7 years ago.
I'm trying to convert a string to number in Javascript, but here is my problem :
var string = "068999999501111443";
parseInt(string); // 68999999501111440
Number(string); // 68999999501111440
Why does this happen and how to fix it ?
Thanks
This is because the number is too large to be stored accurately. It is being stored as a floating point number, which can only store a certain amount of precision. Beyond it's maximum precision, you'll get what look like weird rounding errors.
You'll get similar effects for decimals with a large number of decimal places. This is more well known, as it tends to occur more often, but it's exactly the same effect that is happening here.
Related
This question already has answers here:
Truncate (not round off) decimal numbers in javascript
(32 answers)
Truncate number to two decimal places without rounding
(43 answers)
Closed 4 months ago.
I am trying to figure out how to prevent rounding of numbers when it comes to decimal precisions. I am currently using the .toFixed(2) method to only display two decimal places after the decimal but it is also rounding this figure. For example, if I had a number 19.528 the method Number(19.528).toFixed(2) will yield 19.53 instead of displaying the value 19.52 . Is there anyway or other method to take care of it so that the number does not round?
This question already has answers here:
Node.js Maximum Safe Floating-point Number
(4 answers)
What is JavaScript's highest integer value that a number can go to without losing precision?
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Is floating point math broken?
(31 answers)
Closed 2 years ago.
I am developing a react app and i need to format some numbers using toLocaleString function and i realize that the decimal part of the number changes to zero when the number is very
(10000.25).toLocaleString('en',{maximumFractionDigits: 2, minimumFractionDigits: 2});
//Output: 10,000.25
(10000000000000000000.25).toLocaleString('en',{maximumFractionDigits: 2, minimumFractionDigits: 2});
//Output: 10,000,000,000,000,000,000.00
why is this so? is it a bug or am I missing something?
Javascript compiler cannot handle very large numbers. Use Number.MAX_SAFE_INTEGER to check the last number it can handle. Try to consider using string type from the beginning if these numbers are not calculated (Maybe if you get it from an API kind of), or try using BigInt type.
For floating point, the maximum number it can handle to a precision of 1 decimal digit is 562949953421311 and it differs for other digits. This has been referred here. Try using the BigNumber class in your case.
This question already has answers here:
How to convert a String to long in javascript?
(2 answers)
Closed 4 years ago.
I am trying to convert this "9876543210223023" into integer which is received as a string .I have used parseInt but it gets converted into 9876543210223024.
This is causing failure in my validations .
Please suggest how will the value remain same after conversion.
9876543210223023 is > than 9007199254740991, which is Number.MAX_SAFE_INTEGER.
JavaScript has a Number type, which internally is a 64 bit floating point number.
If the range is too big, the machine episilon is too large, and the number is rounded to the nearest representable number, in this case 9876543210223024.
You need a biginteger library, if you want to process numbers of this size.
If your browser is modern enough (aka Chrome/Chromium), it might have the type "BigInteger" already built-in.
In that case: BigInt("9876543210223023", 10)
Otherwise, the linked BigInt-library will act as polyfill.
This question already has answers here:
Truncate number to two decimal places without rounding
(43 answers)
Closed 5 years ago.
I'm trying to get the first decimals of a float number without any kind of rounding.
Example:
var myfloat = 1.1864526;
myfloat = myfloat.toFixed(2);
It returns 1.19 but I need 1.18.
I'm pretty sure there is an easy solution but I am unable to find it without converting the number to a string (not useful in this case).
Multiply the float value by 100, get the int value of the result then divide that int by 100. Something like this should work:
((int)(myFloat*100)) / 100
This question already has answers here:
How to add a trailing zero to a price?
(3 answers)
Closed 8 years ago.
I want to parse a string and I used parseFloat(), but it removes all the trailing zeroes. How to prevent this - I need to parse the string exactly - if I have 2.5000, I need exactly the same result as a floating-point number - 2.5000.
You can do
parseFloat(2.5).toFixed(4);
If you need exactly the same floating point you may have to figure out the amount
function parseFloatToFixed(string) {
return parseFloat(string).toFixed(string.split('.')[1].length);
}
console.log(parseFloatToFixed('2.54355'));
But i don't really understand why you even need to use parseFloat then? Numbers in javascript do not retain the floating-point count. so you would have to keep them as strings, and calculate against them as floats.
Also don't forget toFixed may have weird rounding issues in different browsers, for example
console.log((0.1).toFixed(20));