I was doing some problems on Leetcode, this one in particular, and I noticed some oddities with how JavaScript handles bigger numbers:

> x = 1000000000000000000000000000001;
1e+30 // Scientific notation? interesting

> x.toString()
'1e+30' // Reason for the parsing issues with my Leetcode implementation..

> x.toLocaleString('en', { useGrouping: false });
'1000000000000000000000000000000' // The last '1' was changed to a '0', probably cause x is stored as 1e+30.

> BigInt(x).toString();
'1000000000000000019884624838656' // ?

> y = 2384762348723648237462348;
2.3847623487236483e+24 // This big number is stored as a floating point?

I tried the string casting of x in Python, and it worked just fine, so I'm assuming this behavior is unique to JavaScript? I'm not too familiar with how JavaScript does things under the hood, so I was hoping I could get an explanation for what's going on here with JavaScript numbers and BigInt? And how would one store x and cast it into a string?

Thanks!