247 lines
5.7 KiB
Markdown
247 lines
5.7 KiB
Markdown
# u8a
|
|
|
|
Utility methods to convert to and from `Uint8Array` objects
|
|
|
|
- [u8aConcat](#u8aconcat) Creates a concatenated Uint8Array from the inputs.
|
|
- [u8aFixLength](#u8afixlength) Shifts a Uint8Array to a specific bitLength
|
|
- [u8aFromBn](#u8afrombn) Creates a Uint8Array value from a BN object.
|
|
- [u8aFromBuffer](#u8afrombuffer) Creates a Uint8Array value from a Buffer object.
|
|
- [u8aFromHex](#u8afromhex) Creates a Uint8Array value from a hex string.
|
|
- [u8aFromString](#u8afromstring) Creates a Uint8Array object from a string.
|
|
- [u8aFromUtf8](#u8afromutf8) Creates a Uint8Array object from a utf-8 string.
|
|
- [u8aToBn](#u8atobn) Creates a BN from a Uint8Array object.
|
|
- [u8aToBuffer](#u8atobuffer) Creates a Buffer object from a hex string.
|
|
- [u8aToHex](#u8atohex) Creates a hex string from a Uint8Array object.
|
|
- [u8aToHexShort](#u8atohexshort) Creates a hex string from a Uint8Array object with max characters.
|
|
- [u8aToString](#u8atostring) Creates a string from a Uint8Array object.
|
|
- [u8aToU8a](#u8atou8a) Creates a Uint8Array value from a Uint8Array bignumber or hex input.
|
|
- [u8aToUtf8](#u8atoutf8) Creates a utf-8 string from a Uint8Array object.
|
|
|
|
## u8aConcat
|
|
|
|
Creates a concatenated Uint8Array from the inputs.
|
|
|
|
```js
|
|
u8aConcat (...values: Array<Uint8Array | string>): Uint8Array
|
|
```
|
|
|
|
|
|
Concatenates the input arrays into a single `UInt8Array`.
|
|
|
|
```js
|
|
import { u8aConcat } from '@polkadot/util';
|
|
|
|
u8aConcat(
|
|
new Uint8Array([1, 2, 3]),
|
|
new Uint8Array([4, 5, 6])
|
|
); // [1, 2, 3, 4, 5, 6]
|
|
```
|
|
|
|
## u8aFixLength
|
|
|
|
Shifts a Uint8Array to a specific bitLength
|
|
|
|
```js
|
|
u8aFixLength (value: string, bitLength: number = -1, withPadding: boolean = false): string
|
|
```
|
|
|
|
|
|
Returns a uint8Array with the specified number of bits contained in the return value. (If bitLength is -1, length checking is not done). Values with more bits are trimmed to the specified length.
|
|
|
|
```js
|
|
import { u8aFixLength } from '@polkadot/util';
|
|
|
|
u8aFixLength('0x12') // => 0x12
|
|
u8aFixLength('0x12', 16) // => 0x0012
|
|
u8aFixLength('0x1234', 8) // => 0x12
|
|
```
|
|
|
|
## u8aFromBn
|
|
|
|
Creates a Uint8Array value from a BN object. [(alias of bnToU8a)](bn.md#bntou8a)
|
|
|
|
```js
|
|
u8aFromBn (value?: BN): Uint8Array
|
|
```
|
|
|
|
|
|
|
|
|
|
|
|
## u8aFromBuffer
|
|
|
|
Creates a Uint8Array value from a Buffer object. [(alias of bufferToU8a)](buffer.md#buffertou8a)
|
|
|
|
```js
|
|
u8aFromBuffer (value?: Buffer): Uint8Array
|
|
```
|
|
|
|
|
|
|
|
|
|
|
|
## u8aFromHex
|
|
|
|
Creates a Uint8Array value from a hex string. [(alias of hexToU8a)](hex.md#hextou8a)
|
|
|
|
```js
|
|
u8aFromHex (value?: string): Uint8Array
|
|
```
|
|
|
|
|
|
|
|
|
|
|
|
## u8aFromString
|
|
|
|
Creates a Uint8Array object from a string.
|
|
|
|
```js
|
|
u8aFromString (value: string): UInt8Array
|
|
```
|
|
|
|
|
|
String input values return the actual encoded `UInt8Array`.
|
|
|
|
```js
|
|
import { u8aFromString } from '@polkadot/util';
|
|
|
|
u8aFromString('hello'); // [0x68, 0x65, 0x6c, 0x6c, 0x6f]
|
|
```
|
|
|
|
## u8aFromUtf8
|
|
|
|
Creates a Uint8Array object from a utf-8 string.
|
|
|
|
```js
|
|
u8aFromUtf8 (value?: string): UInt8Array
|
|
```
|
|
|
|
|
|
String input values return the actual encoded `UInt8Array`. `null` or `undefined` values returns an empty encoded array.
|
|
|
|
```js
|
|
import { u8aFromUtf8 } from '@polkadot/util';
|
|
|
|
u8aFromUtf8('hello'); // [0x68, 0x65, 0x6c, 0x6c, 0x6f]
|
|
```
|
|
|
|
## u8aToBn
|
|
|
|
Creates a BN from a Uint8Array object.
|
|
|
|
```js
|
|
u8aToHex (value?: Uint8Array, isLe: boolean = false): BN
|
|
```
|
|
|
|
|
|
`UInt8Array` input values return the actual BN. `null` or `undefined` values returns an `0x0` value.
|
|
|
|
```js
|
|
import { u8aToBn } from '@polkadot/util';
|
|
|
|
u8aToHex(new Uint8Array([0x68, 0x65, 0x6c, 0x6c, 0xf])); // 0x68656c0f
|
|
```
|
|
|
|
## u8aToBuffer
|
|
|
|
Creates a Buffer object from a hex string.
|
|
|
|
```js
|
|
u8aToBuffer (value?: UInt8Array): Buffer
|
|
```
|
|
|
|
|
|
`null` inputs returns an empty `Buffer` result. `UInt8Array` input values return the actual bytes value converted to a `Buffer`. Anything that is not a `UInt8Array` throws an error.
|
|
|
|
```js
|
|
import { u8aToBuffer } from '@polkadot/util';
|
|
|
|
console.log('Buffer', u8aToBuffer('0x123480001f'));
|
|
```
|
|
|
|
## u8aToHex
|
|
|
|
Creates a hex string from a Uint8Array object.
|
|
|
|
```js
|
|
u8aToHex (value?: UInt8Array): string
|
|
```
|
|
|
|
|
|
`UInt8Array` input values return the actual hex string. `null` or `undefined` values returns an `0x` string.
|
|
|
|
```js
|
|
import { u8aToHex } from '@polkadot/util';
|
|
|
|
u8aToHex(new Uint8Array([0x68, 0x65, 0x6c, 0x6c, 0xf])); // 0x68656c0f
|
|
```
|
|
|
|
## u8aToHexShort
|
|
|
|
Creates a hex string from a Uint8Array object with max characters.
|
|
|
|
```js
|
|
u8aToHexShort (value?: UInt8Array, max: number = 16): string
|
|
```
|
|
|
|
|
|
`UInt8Array` input values return the actual hex string shortened to the specified characters. `null` or `undefined` values returns an `0x` string.
|
|
|
|
```js
|
|
import { u8aToHexShort } from '@polkadot/util';
|
|
|
|
u8aToHexShort(new Uint8Array([0x68, 0x65, 0x6c, 0x6c, 0xf]), 4); // 0x68...0f
|
|
```
|
|
|
|
## u8aToString
|
|
|
|
Creates a string from a Uint8Array object.
|
|
|
|
```js
|
|
u8aToString (value?: UInt8Array): string
|
|
```
|
|
|
|
|
|
`UInt8Array` input values return the actual decoded string. `null` or `undefined` values returns an empty string.
|
|
|
|
```js
|
|
import { u8aToString } from '@polkadot/util';
|
|
|
|
u8aToString(new Uint8Array([21,23,45,67])); // 21,23,45,67
|
|
```
|
|
|
|
## u8aToU8a
|
|
|
|
Creates a Uint8Array value from a Uint8Array bignumber or hex input.
|
|
|
|
```js
|
|
u8aToU8a (value?: Uint8Array | string): Uint8Array
|
|
```
|
|
|
|
|
|
`null` inputs returns a `[]` result, Uint8Array values returns the value, hex strings returns a Uint8Array representation.
|
|
|
|
```js
|
|
import { u8aToU8a } from '@polkadot/util';
|
|
|
|
u8aToU8a(new Uint8Array([0x12, 0x34]); // => Uint8Array([0x12, 0x34])
|
|
u8aToU8a(0x1234); // => Uint8Array([0x12, 0x34])
|
|
```
|
|
|
|
## u8aToUtf8
|
|
|
|
Creates a utf-8 string from a Uint8Array object.
|
|
|
|
```js
|
|
u8aToUtf8 (value?: UInt8Array): string
|
|
```
|
|
|
|
|
|
`UInt8Array` input values return the actual decoded utf-8 string. `null` or `undefined` values returns an empty string.
|
|
|
|
```js
|
|
import { u8aToUtf8 } from '@polkadot/util';
|
|
|
|
u8aToUtf8(new Uint8Array([0x68, 0x65, 0x6c, 0x6c, 0x6f])); // hello
|
|
``` |