Skip to main content

method Buffer.compare

#Buffer.compare(
target: Uint8Array,
targetStart?: number,
targetEnd?: number,
sourceStart?: number,
sourceEnd?: number,
):
-1
| 0
| 1

Compares buf with target and returns a number indicating whether bufcomes before, after, or is the same as target in sort order. Comparison is based on the actual sequence of bytes in each Buffer.

  • 0 is returned if target is the same as buf
  • 1 is returned if target should come beforebuf when sorted.
  • -1 is returned if target should come afterbuf when sorted.
import { Buffer } from 'node:buffer';

const buf1 = Buffer.from('ABC');
const buf2 = Buffer.from('BCD');
const buf3 = Buffer.from('ABCD');

console.log(buf1.compare(buf1));
// Prints: 0
console.log(buf1.compare(buf2));
// Prints: -1
console.log(buf1.compare(buf3));
// Prints: -1
console.log(buf2.compare(buf1));
// Prints: 1
console.log(buf2.compare(buf3));
// Prints: 1
console.log([buf1, buf2, buf3].sort(Buffer.compare));
// Prints: [ <Buffer 41 42 43>, <Buffer 41 42 43 44>, <Buffer 42 43 44> ]
// (This result is equal to: [buf1, buf3, buf2].)

The optional targetStart, targetEnd, sourceStart, and sourceEnd arguments can be used to limit the comparison to specific ranges within target and buf respectively.

import { Buffer } from 'node:buffer';

const buf1 = Buffer.from([1, 2, 3, 4, 5, 6, 7, 8, 9]);
const buf2 = Buffer.from([5, 6, 7, 8, 9, 1, 2, 3, 4]);

console.log(buf1.compare(buf2, 5, 9, 0, 4));
// Prints: 0
console.log(buf1.compare(buf2, 0, 6, 4));
// Prints: -1
console.log(buf1.compare(buf2, 5, 6, 5));
// Prints: 1

ERR_OUT_OF_RANGE is thrown if targetStart < 0, sourceStart < 0, targetEnd > target.byteLength, or sourceEnd > source.byteLength.

Parameters #

#target: Uint8Array

A Buffer or Uint8Array with which to compare buf.

#targetStart: number = 0
optional

The offset within target at which to begin comparison.

#targetEnd: number = target.length
optional

The offset within target at which to end comparison (not inclusive).

#sourceStart: number = 0
optional

The offset within buf at which to begin comparison.

#sourceEnd: number = buf.length
optional

The offset within buf at which to end comparison (not inclusive).

Return Type #

-1
| 0
| 1