What property of Typescript's number or Math.ceil() causes this arithmetic error?-CodePudding

I'm trying to create a function to generate a unique number every time using Typescript. The arithmetic is often incorrect for some reason. I've expanded the logic below and suspect that it has something to do with Typescript/Javascript's number type or Math.ceil(). I'd be grateful if someone could educate me.

function nonce(){
    const millidate = (new Date()).getTime();
    const factor:number = 10000;
    const codeTime:number =  millidate*factor;
    const codeEnd:number = Math.ceil(Math.random()*factor);
    const codeMult:number = Math.ceil(Math.random()*10);
    const codeBody:number = codeTime codeEnd;
    const code:number =  codeBody*codeMult;
    console.log("Breakdown of "   code   ": ", codeTime, codeEnd, codeBody, codeMult);
    return code;
};


nonce();

Image of some tests in Playground

I was using Typescript's Playground to test this, but its performance seems to be the same across different environments.

CodePudding user response：

As pointed out in the comments, your numbers are way over the system limit. Number.MAX_SAFE_INTEGER on my 64-bit system:

9007199254740991 <- MSI
163469121917820770 <- your number

Dial it down, or make strings.

CodePudding user response：

To work with large numbers (more than Number.MAX_SAFE_INTEGER), you need to use BigInt()

Without BigInt:

9007199254740991   1 = 9007199254740992 // Right
9007199254740991   2 = 9007199254740992 // Wrong
9007199254740991   3 = 9007199254740994 // Right

Using BigInt:

9007199254740991n   1n = 9007199254740992n //Right
9007199254740991n   2n = 9007199254740993n //Right
9007199254740991n   3n = 9007199254740994n //Right