[tiptap warn]: Duplicate extension names found: [${duplicate

Error message

[tiptap warn]: Duplicate extension names found: [${duplicatedNames.map(item => `'${item}'`).join(', ')}]. This can lead to issues.

What it means

Error "[tiptap warn]: Duplicate extension names found: [${duplicatedNames.map(item => `'${item}'`).join(', ')}]. This can lead to issues." thrown in ueberdosis/tiptap.

Source

Thrown at packages/core/src/helpers/resolveExtensions.ts:17

import type { Extensions } from '../types.js'
import { findDuplicates } from '../utilities/findDuplicates.js'
import { flattenExtensions } from './flattenExtensions.js'
import { sortExtensions } from './sortExtensions.js'

/**
 * Returns a flattened and sorted extension list while
 * also checking for duplicated extensions and warns the user.
 * @param extensions An array of Tiptap extensions
 * @returns An flattened and sorted array of Tiptap extensions
 */
export function resolveExtensions(extensions: Extensions): Extensions {
  const resolvedExtensions = sortExtensions(flattenExtensions(extensions))
  const duplicatedNames = findDuplicates(resolvedExtensions.map(extension => extension.name))

  if (duplicatedNames.length) {
    console.warn(
      `[tiptap warn]: Duplicate extension names found: [${duplicatedNames
        .map(item => `'${item}'`)
        .join(', ')}]. This can lead to issues.`,
    )
  }

  return resolvedExtensions
}

View on GitHub (pinned to 496d53afd7)

When it happens

Trigger: Thrown at packages/core/src/helpers/resolveExtensions.ts:17 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of ueberdosis/tiptap@496d53afd7 (2026-08-26). Data as JSON: /api/errors/aba2768c5e4c1795. Report an issue: GitHub.