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hex.ts
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hex.ts
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import type { HexString } from '../types.ts';
export const REGEX_HEX_PREFIXED = /^0x[\da-fA-F]+$/;
export const REGEX_HEX_NOPREFIX = /^[\da-fA-F]+$/;
/**
* @name isHex
* @summary Tests for a hex string.
* @description
* Checks to see if the input value is a `0x` prefixed hex string. Optionally (`bitLength` !== -1) checks to see if the bitLength is correct.
* @example
* <BR>
*
* ```javascript
* import { isHex } from 'https://deno.land/x/polkadot@0.2.40/util/mod.ts';
*
* isHex('0x1234'); // => true
* isHex('0x1234', 8); // => false
* ```
*/
export function isHex (value: unknown, bitLength = -1, ignoreLength?: boolean): value is HexString {
return (
typeof value === 'string' && (
value === '0x' ||
REGEX_HEX_PREFIXED.test(value)
)
) && (
bitLength === -1
? (ignoreLength || (value.length % 2 === 0))
: (value.length === (2 + Math.ceil(bitLength / 4)))
);
}