Add spelling and grammar proofing

Proofing helps people catch spelling and grammar mistakes while they write. SuperDoc underlines the issues; a provider you choose checks the text and suggests replacements. It does not include a dictionary or grammar checker.

Try a correction

Expand the Editor and type teh followed by a space. Right-click its underline and choose the. Type teh again and choose Ignore instead: the text stays unchanged, but the issue is dismissed for this editor session.

Enable proofing

Keep the Editor, sample document, and export button from the Quickstart. Create src/proofing-provider.ts with this local provider:

import type { Config } from 'superdoc';

export const proofing = {
  enabled: true,
  provider: {
    id: 'local-example',
    check: async ({ segments, signal }) => {
      signal?.throwIfAborted();
      return {
        issues: segments.flatMap((segment) => {
          return Array.from(
            segment.text.matchAll(/(?<![\p{L}\p{M}\p{N}_])teh(?![\p{L}\p{M}\p{N}_])/gu),
            ({ index }) => ({
              segmentId: segment.id,
              start: index,
              end: index + 3,
              kind: 'spelling' as const,
              replacements: ['the'],
            }),
          );
        }),
      };
    },
  },
} satisfies NonNullable<Config['proofing']>;

Import proofing into src/main.ts in Vanilla or src/App.tsx in React:

import { proofing } from './proofing-provider';

Add proofing to your existing new SuperDoc({ ... }) configuration, or pass proofing={proofing} to SuperDocEditor. Keep your existing readiness and cleanup handlers.

This provider flags only the lowercase word teh, not every spelling mistake. Type teh teh and confirm that both words receive suggestions. It runs locally and needs no service credentials.

Connect a full checker

Use the proofing example for a local English dictionary. Grammar and style checking require a provider that detects those issue kinds; enabling proofing alone does not add them.

SuperDoc sends text segments to the provider after edits. Return each issue with its segmentId and zero-based UTF-16 offsets into that segment, with an exclusive end. Return suggestions in replacements; do not edit the document inside check(). Honor the request's signal so SuperDoc can cancel stale or timed-out checks.

Report provider failures through onProofingError. A failed check does not mean the document has no mistakes.

Save corrected text

Choose a replacement, export with the Quickstart's Export DOCX button, and reopen the file to check the corrected word. Ignore does not replace text or add a word to a persistent dictionary. Use ignoredWords if your application needs to supply its own saved list of words to skip.

Configure proofing

Start with Setup, then open the other groups only when you need them. Proofing runs only when both enabled: true and provider are present.

Options under Reserved are present in the TypeScript type but do not affect the current runtime.

Protect document text

If the provider uses a network, document text leaves the browser. Obtain user consent, send only the required segments over authenticated encrypted transport, define how the service retains and deletes the text, and never include document text in URLs or logs.