JarCastinginteger 
Native 64-bit signed integers in Node.js.
- All standard operators (arithmetic, bitwise, logical)
- Protection from overflow and unsafe numbers
- Always immutable
- Other useful utilities
Installation
npm install --save integer
You must be using Node.js v10 or above. Prebuilt binaries are available for LTS versions + Linux/OSX.
Usage
var Integer = require('integer');
var a = Integer('7129837312139827189');
var b = a.subtract(1).shiftRight(3);
assert(b.equals('891229664017478398'));
Overflow protection
We will not let you perform operations that would result in overflow. If you try to create an Integer that cannot be represented in 64-bits (signed), we will throw a RangeError.
// These will each throw a RangeError
var tooBig = Integer(13897283129).multiply(13897283129);
var tooSmall = Integer.MIN_VALUE.subtract(1);
var divideByZero = Integer(123).divide(0);
var alsoTooBig = Integer('4029384203948203948923');
// You are also protected against two's complement overflow (this will throw a RangeError)
var twosComplement = Integer.MIN_VALUE.divide(-1);
Unsafe number protection
It's easy to convert between me and regular JavaScript numbers.
var int = Integer(12345);
assert(int instanceof Integer);
var num = Number(int); // same as int.toNumber()
assert(typeof num === 'number');
However, we will prevent you from converting an Integer to an unsafe number, and vice-versa. To learn more about unsafe numbers, click here.
// This will throw a RangeError
var unsafe = Integer(Number.MAX_SAFE_INTEGER + 1);
// This is okay
var int = Integer(Number.MAX_SAFE_INTEGER).plus(1);
// But this will throw a RangeError
var unsafe = int.toNumber();
API
Integer(value) -> Integer
Casts a value to an Integer. If the value cannot be converted safely and losslessly, a RangeError is thrown.
var a = Integer();
var b = Integer(12345);
var c = Integer('12345');
assert(a.equals(0));
assert(b.equals(c));
Integer.fromNumber(number, [defaultValue]) -> Integer
Casts a regular number to an Integer.
If the number is unsafe the defaultValue is used instead (or a RangeError is thrown if no defaultValue was provided).
Integer.fromNumber(12345, 0); // results in Integer(12345)
Integer.fromNumber(Number.MAX_SAFE_INTEGER + 1, 0); // results in Integer(0)
Integer.fromString(string, [radix, [defaultValue]]) -> Integer
Casts a string to an Integer. The string is assumed to be base-10 unless a different radix is specified.
If conversions fails the defaultValue is used instead (or a RangeError is thrown if no defaultValue was provided).
var hexColor = 'ff55dd';
var int = Integer.fromString(hexColor, 16, 'ffffff');
Integer.fromBits(lowBits, [highBits]) -> Integer
Creates an Integer by concatenating two regular 32-bit signed integers. The highBits are optional and default to 0.
var int = Integer.fromBits(0x40, 0x20);
int.toString(16); // => '2000000040'
Arithmetic operations
.add/plus(other) -> Integer
.subtract/sub/minus(other) -> Integer
.multiply/mul/times(other) -> Integer
.divide/div/divideBy/dividedBy/over(other) -> Integer
.modulo/mod(other) -> Integer
Performs the arithmetic operation and returns a new Integer. The argument must either be a number, a base-10 string, or an Integer. If the operation results in overflow, a RangeError is thrown.
.negate/neg() -> Integer
Returns the unary negation (-value) of the Integer.
.abs/absoluteValue() -> Integer
Returns the absolute value of the Integer.
Bitwise operations
.and(other) -> Integer
.or(other) -> Integer
.xor(other) -> Integer
.not() -> Integer
Performs the bitwise operation and returns a new Integer. The argument must either be a number, a base-10 string, or an Integer.
.shiftLeft/shl(numberOfBits) -> Integer
.shiftRight/shr(numberOfBits) -> Integer
Shifts the Integer by specified number of bits and returns the result.
Logical operations
.equals/eq/isEqualTo(other) -> boolean
.notEquals/neq/isNotEqualTo/doesNotEqual(other) -> boolean
.greaterThan/gt/isGreaterThan(other) -> boolean
.lessThan/lt/isLessThan(other) -> boolean
.greaterThanOrEquals/gte/isGreaterThanOrEqualTo(other) -> boolean
.lessThanOrEquals/lte/isLessThanOrEqualTo(other) -> boolean
Performs the logical operation and returns true or false. The argument must either be a number, a base-10 string, or an Integer.
.compare(other) -> number
Compares the value of the Integer and other, resulting in:
-1ifthisis less thanother1ifthisis greater thanother0ifthisis equal toother
Converting to other values
.toString([radix]) -> string
Converts the Integer to a string. A base-10 string is returned unless a different radix is specified.
.valueOf/toNumber() -> number
Converts the Integer to a regular number. If the Integer is not within the safe range, a RangeError is thrown.
.toNumberUnsafe() -> number
Converts the Integer to a regular number, even if the conversion would result in a loss of precision. This method will never throw an error.
Other utility
.bitSizeAbs() -> number
Returns the number of bits necessary to hold the absolute value of the Integer.
Integer(0).bitSizeAbs(); // => 1
Integer(128).bitSizeAbs(); // => 8
Integer(-255).bitSizeAbs(); // => 8
Integer.fromString('4fffffffffff', 16).bitSizeAbs(); // => 47
.isEven() -> boolean
.isOdd() -> boolean
.isPositive() -> boolean
.isNegative() -> boolean
.isZero() -> boolean
.isNonZero/isNotZero() -> boolean
These methods are self-explanatory.
.isSafe() -> boolean
.isUnsafe() -> boolean
Returns whether or not the Integer is within the safe range. If it's not within the safe range, trying to convert it to a regular number would result in a RangeError being thrown.
The safe range is defined as n >= Number.MIN_SAFE_INTEGER && n <= Number.MAX_SAFE_INTEGER.
Integer.isInstance(value) -> boolean
Determines if the given value is an Integer object.
Getters
- .low -> number - the lower 32-bits of the
Integer - .high -> number - the upper 32-bits of the
Integer
Constants
- Integer.MAX_VALUE - maximum value of an
Integer - Integer.MIN_VALUE - minimum value of an
Integer - Integer.ZERO - an
Integerwith a value of0 - Integer.ONE - an
Integerwith a value of1 - Integer.NEG_ONE - an
Integerwith a value of-1