54 lines
1.2 KiB
Markdown
54 lines
1.2 KiB
Markdown
# bn
|
|
|
|
Utility methods to convert to and from `BN` objects
|
|
|
|
- [bnFromHex](#bnfromhex) Creates a BN.js bignumber object from a hex string.
|
|
- [bnToHex](#bntohex) Creates a hex value from a BN.js bignumber object.
|
|
- [bnToU8a](#bntou8a) Creates a Uint8Array object from a BN.
|
|
|
|
## bnFromHex
|
|
|
|
Creates a BN.js bignumber object from a hex string. [(alias of hexToBn)](hex.md#hextobn)
|
|
|
|
```js
|
|
bnFromHex (value?: string): BN
|
|
```
|
|
|
|
|
|
|
|
|
|
|
|
## bnToHex
|
|
|
|
Creates a hex value from a BN.js bignumber object.
|
|
|
|
```js
|
|
bnToHex (value?: BN, bitLength: number = -1): string
|
|
```
|
|
|
|
|
|
`null` inputs returns a `0x` result, BN values return the actual value as a `0x` prefixed hex value. Anything that is not a BN object throws an error. With `bitLength` set, it fixes the number to the specified length.
|
|
|
|
```js
|
|
import BN from 'bn.js';
|
|
import { bnToHex } from '@polkadot/util';
|
|
|
|
bnToHex(new BN(0x123456)); // => '0x123456'
|
|
```
|
|
|
|
## bnToU8a
|
|
|
|
Creates a Uint8Array object from a BN.
|
|
|
|
```js
|
|
bnToU8a (value?: BN): Uint8Array
|
|
```
|
|
|
|
|
|
`null`/`undefined`/`NaN` inputs returns an empty `Uint8Array` result. `BN` input values return the actual bytes value converted to a `Uint8Array`.
|
|
|
|
```js
|
|
import { bnToU8a } from '@polkadot/util';
|
|
|
|
bnToU8a(new BN(0x1234)); // => [0x12, 0x34]
|
|
``` |