BigInt.asUintN()

The BigInt.asUintN static method clamps a BigInt value to the given number of bits, and returns that value as an unsigned integer.

Syntax

BigInt.asUintN(bits, bigint)

Parameters

• bits
  • : The amount of bits available for the returned BigInt. Should be an integer between 0 and 2⁵³ - 1, inclusive.
• bigint
  • : The BigInt value to clamp to fit into the supplied bits.

Return value

The value of bigint modulo 2^bits, as an unsigned integer.

Exceptions

• RangeError
  • : Thrown if bits is negative or greater than 2⁵³ - 1.

Description

The BigInt.asUintN method clamps a BigInt value to the given number of bits, and interprets the result as an unsigned integer. Unsigned integers have no sign bits and are always non-negative. For example, for BigInt.asUintN(4, 25n), the value 25n is clamped to 9n:

25n = 00011001 (base 2)
         ^==== Clamp to four remaining bits
===>      1001 (base 2) = 9n

Note: BigInt values are always encoded as two's complement in binary.

Unlike similar language APIs such as Number.prototype.toExponential(), asUintN is a static property of BigInt, so you always use it as BigInt.asUintN(), rather than as a method of a BigInt value. Exposing asUintN() as a "standard library function" allows interop with asm.js.