The BigInt.asIntN
static method clamps a BigInt
value to the given number of bits, and returns that value as a signed integer.
The BigInt.asIntN
static method clamps a BigInt
value to the given number of bits, and returns that value as a signed integer.
BigInt.asIntN(bits, bigint);
bits
The amount of bits available for the integer size.
bigint
The BigInt value to clamp to fit into the supplied bits.
The value of bigint
modulo 2^bits
, as a signed integer.
The BigInt.asIntN
method clamps a BigInt
value to the given number of bits, and interprets the result as a signed integer. For example, for BigInt.asIntN(3, 25n)
, the value 25n
is clamped to 1n
:
25n = 00011001 (base 2) ^=== Clamp to three remaining bits ===> 001 (base 2) = 1n
If the leading bit of the remaining number is 1
, the result is negative. For example, BigInt.asIntN(4, 25n)
yields -7n
, because 1001
is the encoding of -7
under two's complement:
25n = 00011001 (base 2) ^==== Clamp to four remaining bits ===> 1001 (base 2) = -7n
Note: BigInt
values are always encoded as two's complement in binary.
The BigInt.asIntN()
method can be useful to stay in the range of 64-bit arithmetic.
const max = 2n ** (64n - 1n) - 1n; BigInt.asIntN(64, max); // ↪ 9223372036854775807n BigInt.asIntN(64, max + 1n); // ↪ -9223372036854775808n // negative because the 64th bit of 2^63 is 1
Specification |
---|
ECMAScript Language Specification # sec-bigint.asintn |
Desktop | Mobile | Server | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | WebView Android | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | Deno | Node.js | |
asIntN |
67 |
79 |
68 |
No |
54 |
14 |
67 |
67 |
68 |
48 |
14 |
9.0 |
1.0 |
10.4.0 |
© 2005–2022 MDN contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt/asIntN