JavaScript 将科学记数法中的不安全整数转换为字符串

Question

I have one API for generate a random map tileset with a Erlang server, with safe integer JavaScript can request to API good but the problem is when is more than Number.MAX_SAFE_INTEGER .

Then, in the server I haven't the integer becuse JavaScript send 1e+21 number in scientific notation, not 999999999999999999999 and I need the number like string not in scientific notation.

How can I get a string like "999999999999999999999" in JavaScript for send to API that and not scientific notation string? Exists a library for arbitrary long numbers in JavaScript small only for the number? The umber is a X and Y number of position and need the correct position, and not is good a big library because need good performance for render the map in ms, is for a game in browser, not for astronomy calc.

Answer 1

you could use the BigNumber library ( https://github.com/MikeMcl/bignumber.js/ ).

These 2 lines should do the trick:

BigNumber.config({EXPONENTIAL_AT: [-10, 30]});
var stringifiedLongNumber = new BigNumber('999999999999999999999').toString();

EXPONENTIAL_AT config parameter documentation: http://mikemcl.github.io/bignumber.js/#exponential-at

Answer 2

Maybe is better a small solution using optimizations of asm.js and work with strings for add and rest to the number, this a example simple but is possible do better:

var a = "999999";
var b = "";
var acarreo = 1|0;
console.log(a);
for(var i=a.length-1|0; i >= 0; i--){
    var j = parseInt(a[i])|0;
    var j = j + acarreo|0;
    if(j > 9){
        j-=10|0;
        acarreo=1|0;
    }else{
        acarreo=0|0;
    }
    b = j.toString() + b;
}
if(acarreo>0){
    a = acarreo.toString() + b;
}else{
    a = b;
}
console.log(a);

Answer 3

在这种情况下，一种可能的解决方案是不向服务器发送新位置，而只发送一个移动事件，然后 Erlang 中的服务器可以计算任意长数字的新位置（同时有足够的内存来处理非常大的数字），并且在 JavaScript 中没有问题。