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denoland-deno/std/bytes/README.md

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# 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.
```typescript
import { indexOf } from "https://deno.land/std@$STD_VERSION/bytes/mod.ts";
indexOf(
new Uint8Array([1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 3]),
new Uint8Array([0, 1, 2]),
); // => returns 2
indexOf(
new Uint8Array([1, 2, 0, 1, 2, 0, 1, 2, 0, 1, 3]),
new Uint8Array([0, 1, 2]),
3,
); // => returns 5
```
## lastIndexOf
Find last index of binary pattern from given binary array, or -1 if it is not
present.
```typescript
import { lastIndexOf } from "https://deno.land/std@$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.
```typescript
import { equals } from "https://deno.land/std@$STD_VERSION/bytes/mod.ts";
equals(new Uint8Array([0, 1, 2, 3]), new Uint8Array([0, 1, 2, 3])); // returns true
equals(new Uint8Array([0, 1, 2, 3]), new Uint8Array([0, 1, 2, 4])); // returns false
```
## startsWith
Check whether binary array starts with prefix.
```typescript
import { startsWith } from "https://deno.land/std@$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.
```typescript
import { endsWith } from "https://deno.land/std@$STD_VERSION/bytes/mod.ts";
endsWith(new Uint8Array([0, 1, 2]), new Uint8Array([0, 1])); // returns false
endsWith(new Uint8Array([0, 1, 2]), new Uint8Array([1, 2])); // returns true
```
## repeat
Repeat bytes of given binary array and return new one.
```typescript
import { repeat } from "https://deno.land/std@$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.
```typescript
import { concat } from "https://deno.land/std@$STD_VERSION/bytes/mod.ts";
concat(new Uint8Array([1, 2]), new Uint8Array([3, 4])); // returns Uint8Array(4) [ 1, 2, 3, 4 ]
concat(
new Uint8Array([1, 2]),
new Uint8Array([3, 4]),
new Uint8Array([5, 6]),
new Uint8Array([7, 8]),
); // => returns Uint8Array(8) [ 1, 2, 3, 4, 5, 6, 7, 8 ]
```
## contains
Check source array contains pattern array.
```typescript
import { contains } from "https://deno.land/std@$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.
```typescript
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
```