denoland-deno/std/bytes

bytes

bytes module is made to provide helpers to manipulation of bytes slice.

usage

All the following functions are exposed in mod.ts.

indexOf

Find first index of binary pattern from given binary array, or -1 if it is not present.

import { indexOf } from "https://deno.land/std@$STD_VERSION/bytes/mod.ts";

indexOf(
  new Uint8Array([1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 3]),
  new Uint8Array([0, 1, 2]),
); // => returns 2

indexOf(
  new Uint8Array([1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 3]),
  new Uint8Array([0, 1, 2]),
  3,
); // => returns 5

lastIndexOf

Find last index of binary pattern from given binary array, or -1 if it is not present.

import { lastIndexOf } from "https://deno.land/std@$STD_VERSION/bytes/mod.ts";

lastIndexOf(
  new Uint8Array([0, 1, 2, 3, 3, 0, 1, 2]),
  new Uint8Array([0, 1, 2]),
); // => returns 5

lastIndexOf(
  new Uint8Array([0, 1, 2, 3, 3, 0, 1, 2]),
  new Uint8Array([0, 1, 2]),
  3,
); // => returns 0

equals

Check whether given binary arrays are equal to each other.

import { equals } from "https://deno.land/std@$STD_VERSION/bytes/mod.ts";

equals(new Uint8Array([0, 1, 2, 3]), new Uint8Array([0, 1, 2, 3])); // returns true
equals(new Uint8Array([0, 1, 2, 3]), new Uint8Array([0, 1, 2, 4])); // returns false

startsWith

Check whether binary array starts with prefix.

import { startsWith } from "https://deno.land/std@$STD_VERSION/bytes/mod.ts";

startsWith(new Uint8Array([0, 1, 2]), new Uint8Array([0, 1])); // returns true
startsWith(new Uint8Array([0, 1, 2]), new Uint8Array([1, 2])); // returns false

endsWith

Check whether binary array ends with suffix.

import { endsWith } from "https://deno.land/std@$STD_VERSION/bytes/mod.ts";

endsWith(new Uint8Array([0, 1, 2]), new Uint8Array([0, 1])); // returns false
endsWith(new Uint8Array([0, 1, 2]), new Uint8Array([1, 2])); // returns true

repeat

Repeat bytes of given binary array and return new one.

import { repeat } from "https://deno.land/std@$STD_VERSION/bytes/mod.ts";

repeat(new Uint8Array([1]), 3); // returns Uint8Array(3) [ 1, 1, 1 ]

concat

Concatenate multiple binary arrays and return new one.

import { concat } from "https://deno.land/std@$STD_VERSION/bytes/mod.ts";

concat(new Uint8Array([1, 2]), new Uint8Array([3, 4])); // returns Uint8Array(4) [ 1, 2, 3, 4 ]

concat(
  new Uint8Array([1, 2]),
  new Uint8Array([3, 4]),
  new Uint8Array([5, 6]),
  new Uint8Array([7, 8]),
); // => returns Uint8Array(8) [ 1, 2, 3, 4, 5, 6, 7, 8 ]

contains

Check source array contains pattern array.

import { contains } from "https://deno.land/std@$STD_VERSION/bytes/mod.ts";

contains(
  new Uint8Array([1, 2, 0, 1, 2, 0, 2, 1, 3]),
  new Uint8Array([0, 1, 2]),
); // => returns true

contains(
  new Uint8Array([1, 2, 0, 1, 2, 0, 2, 1, 3]),
  new Uint8Array([2, 2]),
); // => returns false

copy

Copy bytes from one binary array to another.

import { copy } from "https://deno.land/std@$STD_VERSION/bytes/mod.ts";

const dst = new Uint8Array(4);
const src = Uint8Array.of(1, 2, 3, 4);
const len = copy(src, dest); // returns len = 4