nostr-tools/nip27.ts

import * as nip19 from './nip19'
import * as nip21 from './nip21'

/** Regex to find NIP-21 URIs inside event content. */
export const regex = () =>
  new RegExp(`\\b${nip21.NOSTR_URI_REGEX.source}\\b`, 'g')

/** Match result for a Nostr URI in event content. */
export interface NostrURIMatch extends nip21.NostrURI {
  /** Index where the URI begins in the event content. */
  start: number
  /** Index where the URI ends in the event content. */
  end: number
}

/** Find and decode all NIP-21 URIs. */
export function * matchAll(content: string): Iterable<NostrURIMatch> {
  const matches = content.matchAll(regex())

  for (const match of matches) {
    const [uri, value] = match

    yield {
      uri: uri as `nostr:${string}`,
      value,
      decoded: nip19.decode(value),
      start: match.index!,
      end: match.index! + uri.length
    }
  }
}

/**
 * Replace all occurrences of Nostr URIs in the text.
 *
 * WARNING: using this on an HTML string is potentially unsafe!
 *
 * @example
 * ```ts
 * nip27.replaceAll(event.content, ({ decoded, value }) => {
 *   switch(decoded.type) {
 *     case 'npub':
 *       return renderMention(decoded)
 *     case 'note':
 *       return renderNote(decoded)
 *     default:
 *       return value
 *   }
 * })
 * ```
 */
export function replaceAll(
  content: string,
  replacer: (match: nip21.NostrURI) => string
): string {
  return content.replaceAll(regex(), (uri, value) => {
    return replacer({
      uri: uri as `nostr:${string}`,
      value,
      decoded: nip19.decode(value)
    })
  })
}