long

What is long?

The 'long' npm package provides a comprehensive library for representing, converting, and performing arithmetic operations on 64-bit integers. This is particularly useful in environments like JavaScript, where the standard Number type can only safely represent integers up to 53 bits.

What are long's main functionalities?

Creation of Long integers

This feature allows the creation of 64-bit integers. The constructor takes two arguments representing the low and high 32 bits of the integer, respectively.

const Long = require('long');
let longVal = new Long(0xFFFFFFFF, 0x7FFFFFFF);

Arithmetic operations

This feature supports basic arithmetic operations such as addition, subtraction, multiplication, and division on 64-bit integers.

const Long = require('long');
let long1 = new Long(1, 0);
let long2 = new Long(1, 0);
let sum = long1.add(long2);

Comparison operations

This feature enables comparison operations like less than, greater than, equals, etc., between two Long instances.

const Long = require('long');
let long1 = new Long(1, 0);
let long2 = new Long(2, 0);
let isLessThan = long1.lessThan(long2);

Other packages similar to long

bignum

The 'bignum' package also provides arbitrary precision arithmetic operations. Unlike 'long', which is limited to 64-bit, 'bignum' can handle much larger numbers, making it suitable for applications requiring high precision.

bigint

Similar to 'long', 'bigint' supports large integer operations. However, 'bigint' is built into modern JavaScript environments as a native type, offering better performance and integration with the language compared to 'long', which is a library.

README

Long.js

A Long class for representing a 64-bit two's-complement integer value derived from the Closure Library for stand-alone use and extended with unsigned support.

Why?

As of the ECMAScript specification, number types have a maximum value of 2^53. Beyond that, JavaScript falls back to double internally. Furthermore, bitwise operations are always performed on 32bit numbers. However, in some use cases it is required to be able to perform reliable mathematical and/or bitwise operations on the full 64bits. This is where Long.js comes into play.

Long.js is based on the goog.math.Long class from the Closure Library. It uses two 32bit integers internally and provides methods for comparison, common tests, math and bitwise operations on the full 64bits. Additionally, some use cases also require to work with 64bit unsigned values, so Long.js has been extended with unsigned support while maintaining compatibility to the Closure Library implementation.

Features

• CommonJS compatible
• RequireJS/AMD compatible
• Shim compatible (include the script, then use var Long = dcodeIO.Long;)
• node.js compatible, also available via npm
• Fully documented using jsdoc3
• Zero production dependencies
• Small footprint

Long

• Construction from high and low bits as 32bit integers: new Long(low, high[, unsigned=false]) and Long.fromBits(low, high[, unsigned=false])
• ...from a 32bit integer: Long.fromInt(value[, unsigned=false]) including a cache for frequently used small numbers
• ...from a number which may internally be a number or double type: Long.fromNumber(value[, unsigned=false])
• ...from a string: Long.fromString(value[, unsigned=false, radix=10])
• Conversion to a 32bit integer: Long#toInt()
• ...to a number: Long#toNumber()
• ...to a string: Long#toString([radix=10])
• Getters for high and low bits as 32bit integers: Long#getLowBits(), Long#getHighBits() and Long#getLowBitsUnsigned(), Long#getHighBitsUnsigned()
• Comparison: Long#equals(other), Long#notEquals(other), Long#lessThan(other), Long#lessThanOrEqual(other), Long#greaterThan(other), Long#greaterThanOrEqual(other), Long#compare(other)
• Common tests: Long#isZero(), Long#isNegative(), Long#isOdd(), Long#isEven()
• Math: Long#negate(), Long#add(other), Long#subtract(other), Long#multiply(other), Long#div(other), Long#modulo(other)
• Bitwise operations: Long#not(), Long#and(other), Long#or(other), Long#xor(other), Long#shiftLeft(numBits), Long#shiftRight(numBits), Long#shiftRightUnsigned(numBits)
• Conversion between signed and unsinged: Long.toSigned(), Long.toUnsigned()

Usage

node.js / CommonJS

Install: npm install long

var Long = require("Long");
var longVal = new Long(0xFFFFFFFF, 0x7FFFFFFF);
console.log(longVal.toString());
...

RequireJS / AMD

require.config({
    "paths": {
        "Math/Long": "/path/to/Long.js"
    }
});
require(["Math/Long"], function(Long) {
    var longVal = new Long(0xFFFFFFFF, 0x7FFFFFFF);
    console.log(longVal.toString());
});

Browser / shim

<script src="//raw.github.com/dcodeIO/Long.js/master/Long.min.js"></script>

var Long = dcodeIO.Long;
var longVal = new Long(0xFFFFFFFF, 0x7FFFFFFF);
alert(longVal.toString());

Documentation

• View documentation

Downloads

• ZIP-Archive
• Tarball

License

Apache License, Version 2.0 - http://www.apache.org/licenses/LICENSE-2.0.html