Unsigned 64-bit integers.
This package exists because while modern JavaScript environments support very
large integers via the BigInt
type, it is not available in older browsers and tooling doesn't always
transpile BigInt
operations into a backwards-compatible format.
U64
also turned out to be more performant than BigInt
in tests. @pacote
's
implementation of the XXH64 algorithm based on U64
is 4.5 times faster than
the one based on BigInt
, although optimizations to JavaScript runtimes might
change this in the future.
If you target ECMAScript 2020 or later, and you do not care about the differences in performance, you will probably not need this.
The U64
type provided by this package is represented as a tuple of four 16-bit
integers. For example, the number 1 is [1, 0, 0, 0]
. It is not an object class
with built-in methods. Instead of methods, the package provides functions to
support commonly-used operations.
yarn add @pacote/u64
import { add, from, toString } from '@pacote/u64'
const result = add(from('1609587929392839161'), from('9650029242287828579'))
toString(result) // -> '11259617171680667740'
Compares two U64
values and returns true
if they are numerically equivalent,
otherwise returns false
.
Compares two U64
values and returns true
if a
is smaller than b
,
otherwise returns false
.
Compares two U64
values and returns true
if a
is greater than b
,
otherwise returns false
.
The bitwise AND function returns a 1
in each bit position for which the
corresponding bits of both operands are 1
s. Equivalent to the numeric &
operator.
The bitwise OR function returns a 1
in each bit position for which the
corresponding bits of either operand are 1
s. Equivalent to the numeric |
operator.
The bitwise XOR function returns a 1
in each bit position for which the
corresponding bits of either but not both operands are 1
s. Equivalent to the
numeric ^
operator.
The left rotate function circularly shifts the value
the specified number of
bits
to the left. Bits shifted off to the left appear on the right.
The right rotate function circularly shifts the value
the specified number of
bits
to the right. Bits shifted off to the right appear on the left.
The left shift function shifts the value
the specified number of bits
to the
left. Excess bits shifted off to the left are discarded. Zero bits are shifted
in from the right. Equivalent to the numeric <<
operator.
The right shift function shifts the value
the specified number of bits
to
the right. Excess bits shifted off to the right are discarded. Zero bits are
shifted in from the left. The sign bit becomes 0, so the result is always
non-negative. Equivalent to the numeric >>>
operator.
Coerces a U64
value to number
.
Because JavaScript numbers are not 64-bit, precision may be lost when
converting. Only numbers with up to 32-bit precision (2^32, or 4294967296)
can be safely converted into number
.
Returns a string representing the value
in the specified radix
(base). If
not provided radix
defaults to 10
.
MIT © Luís Rodrigues.