function util.hexHasPrefiximport { util } from "https://dotland.deno.dev/x/polkadot@0.2.35/mod.ts"; const { hexHasPrefix } = util; hexHasPrefix(value?: string | null): value is HexStringExamples import { hexHasPrefix } from 'https://deno.land/x/polkadot@0.2.35/util/mod.ts'; console.log('has prefix', hexHasPrefix('0x1234')); // => true Parametersoptionalvalue: string | nullReturnsvalue is HexString