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common/docs/hex.md
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2017-11-21 00:11:09 +01:00

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hex

Internal utilities to create and test for hex values

  • (hexAddPrefix)[#hexAddPrefix] Adds the 0x prefix to string values.
  • (hexHasPrefix)[#hexHasPrefix] Tests for the existence of a 0x prefix.
  • (hexStripPrefix)[#hexStripPrefix] Strips any leading 0x prefix.

hexAddPrefix

Adds the 0x prefix to string values.

hexAddPrefix (value: ?string): string

Returns a 0x prefixed string from the input value. If the input is already prefixed, it is returned unchanged.

import { hexAddPrefix } from '@polkadot/util';

console.log('With prefix', hexAddPrefix('0a0b12')) // => 0x0a0b12

hexHasPrefix

Tests for the existence of a 0x prefix.

hexHasPrefix (value: ?string): boolean

Checks for a valid hex input value and if the start matched 0x

import { hexHasPrefix } from '@polkadot/util';

console.log('has prefix', hexHasPrefix('0x1234')); // => true

hexStripPrefix

Strips any leading 0x prefix.

hexStripPrefix (value: ?string): string

Tests for the existence of a 0x prefix, and returns the value without the prefix. Un-prefixed values are returned as-is.

import { hexStripPrefix } from '@polkadot/util';

console.log('stripped', hexStripPrefix('0x1234')); // => 1234