r-add

Just because javascript can't calculate with large or float number, a cross-browser, numerically stable way to add numbers in javascript.

Installation

npm i r-add

Usage

var add = require('r-add');
var a = 0.1;
var b = 0.2;

// the bad solution
console.log(a + b); // prints 0.30000000000000004

// the good solution
add(a, b, function (err, result){
  console.log(result); // prints 0.3
});

Why?

Because the javascript uses IEEE 754 standard and it has only 64 bit for numbers. From this 52 bit for value and 11 bit for exponent and 1 for sign. This is the reason for max safe integer is 9007199254740991. This number is the maximum which javascript can calculate precisely.

For example:

var a = 9007199254740991 + 1;
var b = 9007199254740991 + 2;
console.log(a == b); // prints true

Of course the type of this numbers are number but for maniacs the example works with type safe relation operator too:

var a = 9007199254740991 + 1;
var b = 9007199254740991 + 2;
console.log(a === b); // prints true

And the maximum value of a number in javascript is only 1.7976931348623157e+308

It is unsuitable for precise scientific calculations.

Why string?

See above :)

The numbers cannot store the precise value of large or extreme accurate values. The strings can.