This question already has answers here:
JavaScript summing large integers
(10 answers)
Closed 5 years ago.
I am using the Number() JS function which is supposed to convert string value to numeric.
It's working fine for small numbers. For big ones - it is starting to substitude values with zeros as shown on the image:
Is there a work around for this problem?
In JS, the largest integral value is 9007199254740991 That is, all the positive and negative integers should not exceed the -9007199254740991 and 9007199254740991 respectively.
The same is defined as the 253-1.
console.log(Number.isSafeInteger(parseInt('1111111111')))
console.log(parseInt('1111111111'))
console.log(Number.isSafeInteger(parseInt('111111111111111111')))
console.log(parseInt('111111111111111111'))
//9007199254740991 - The largest JS Number
console.log(Number.isSafeInteger(parseInt('9007199254740991')))
This is because you're using numbers that are larger than Number.MAX_SAFE_INTEGER and Javascript does not guarantee to represent these numbers correctly
Use Number.isSafeInteger to check:
> Number.isSafeInteger(Number('111111111111111111'))
< false
Related
This question already has answers here:
What is JavaScript's highest integer value that a number can go to without losing precision?
(21 answers)
Large numbers erroneously rounded in JavaScript
(6 answers)
javascript large integer round because precision? (why?)
(2 answers)
Closed 1 year ago.
So, I found something I couldn't understand and can't find any internet resource that explains it.
Please see the code below:
var num = 35422484817926290
// subtract 5 from num
console.log(num-5)
Output (Wrong) : 35422484817926284
I checked it in Node, Opera, and Chrome, all of them give the wrong answers.
I do understand the fact that arithmetic with unsafe Integers in JS is faulty, for example:
console.log(100000000000000005-1)
Output (Wrong) : 100000000000000000
So what's the deal with big number arithmetic in JS?
When I run this code:
var num = 35422484817926290
// subtract 5 from num
console.log(num-5)
in Visual Studio Code, i get the following warning:
"Numeric literals with absolute values equal to 2^53 or greater are too large to be represented accurately as integers."
So the correct way to make this calculation would be like this:
var num = 35422484817926290n
// subtract 5 from num
console.log(num-5n)
JavaScript is not faulty, this is how the Floating point arithmetic works. Looks duplicate to this post. For better calculation involving floating-point numbers you should use BigNumber API.
This question already has answers here:
Javascript compare numbers as strings
(2 answers)
Closed 2 years ago.
When the smaller number string when compared with the larger number string - the result is true.
How is it possible?
document.write(`Why the result of '2'>'10' is ${'2'>'10'}`)
Any expert here?
You're comparing strings, so a lexical comparison is performed instead of a numerical comparison.
Lexically, 2 comes after 1.
This question already has answers here:
Is floating point math broken?
(31 answers)
How to deal with floating point number precision in JavaScript?
(47 answers)
Closed 3 years ago.
When I run a “For” loop and I log the index used in it with increments of 0.1 , starting from 1, the outcome is not a number with a single decimal digit, but something with multiple decimal digits (code and results are shown here below).
for (let i = 1; i <= 2; i += 0.1) {
console.log(i);
};
What I expected is to see the following series:
1
1.1
1.2
1.3
...
instead what I actually get is:
1
1.1
1.2000000000000002
1.3000000000000003
1.4000000000000004
1.5000000000000004
1.6000000000000005
1.7000000000000006
1.8000000000000007
1.9000000000000008
This happens in every browser, in the same way either I compile the loop directly in the Console DOM or I code within Visual Studio Code.
Does anyone have an explanation about it?
Have you tried incrementing by 0.100000000000000?
Or using i = i.toFixed(1)? This will round the number to one decimal place. May not be what you need as toFixed will convert the number to a string
This question already has answers here:
Number with leading zero in JavaScript
(3 answers)
Closed 3 years ago.
I guess I can format it back. I'm just interested in why it's happening.
function test(d){
console.log(d) // 151028224
}
console.log(test(00001100101000))
By default, any number literally written with a zero at the beginning is considered as octal (base 8) number representation, and then, when you show back any number with console.log, it is written as its base 10 representation.
console.log(05)
console.log(06)
console.log(07)
console.log(010)
console.log(011)
It's recommended to avoid this in code, because it can lead to confusions :
if the number contains the digits 8 or 9, it cannot be a base-8 number, and thus treated as base 10 !
console.log(05)
console.log(06)
console.log(07)
console.log(08) // Yiiik !
console.log(09) // Yiiik !
console.log(010)
console.log(011)
The function has nothing to do with it.
The JavaScript compiler converts your number literal into a Number when it compiles the source code.
Since the number starts with a 0, it is treated as octal instead of decimal.
This question already has answers here:
Large numbers erroneously rounded in JavaScript
(6 answers)
Closed 7 years ago.
I have the folowing code:
Click
function Add(id) {
alert(id);
}
The value in the alert is 23905762501722144 (-2) from the original value.
Why does this happen?
https://jsfiddle.net/wvtqostd/4/
log2(23905762501722146) ~= 54.408
JavaScript stores all numbers - including integers - as double precision floats. Double precision mantissa/significand contains 52 bits of information, so some information gets lost storing so long/precise number as you have.
Because 23905762501722144 is to big to represent as integer value... try sending it as string value.