Sentence Capitalizer

Sentence Case and Dash Autocorrect

An Obsidian plugin that fixes a few specific annoyances Word and LibreOffice handle but Obsidian doesn't:

1. Capitalize first letter of every sentence when you forget to press Shift.
2. Correct TWo INitial CApitals.
3. Replace dashes with en- or em-dashes.

I tried a couple of existing autocorrect plugins first, but each rescanned the whole line on every keystroke thus fighting you by re-capitalizing letters you deliberately typed lowercase, undo didn't cleanly revert just the auto-capitalization, and also did more than these specific fixes, so this plugin exists to do exactly these little things correctly.

When you finish typing a word — by pressing space, a punctuation mark, or Enter — its first letter is capitalized if that word starts a sentence. This mirrors Word/LibreOffice: nothing happens while you're still composing the word, so you're always free to type a deliberate lowercase letter there, correction only happens once, on the word-ending keystroke.

A single Cmd/Ctrl+Z right after correction undoes just it, without touching the rest of the word or the space/punctuation after it.

What counts as "start of a sentence"

• The very start of the note
• The very start of a line
• Right after ., !, or ? (optionally followed by closing quotes/brackets) and whitespace
• Right after a blockquote marker (>, >>, ...)
• Right after a list marker (-, *, +, 1., 1), including - [ ] checkboxes) — off by default, enable "Capitalize list items" in the plugin's settings

Code blocks and inline code spans are never touched, detected via Obsidian's own syntax tree rather than pattern-matching.

Fix two initial capitals

Mirrors Word/LibreOffice's "Correct TWo INitial CApitals": if a word starts with two capital letters followed by a lowercase letter (like THe or ABout), the second letter is lowercased once you finish typing the word, on the same word-ending keystroke as sentence capitalization.

You can list exact words to always skip in the plugin's settings ("Two initial capitals exceptions"), comma-separated, case-sensitive.

Autocorrect dashes

Converts hyphens into en or em dashes once you finish typing the word after them, mirroring Word/LibreOffice's dash autoformat:

• word--word (no spaces) => word—word (em dash)
• word - word or word -- word (spaces on both sides) => word – word (en dash, spaces kept)
• A single hyphen with no surrounding spaces, like well-known, is always left alone.

Install (manual)

npm install --legacy-peer-deps
npm run build

(--legacy-peer-deps is needed because the obsidian types package pins an exact peer version of @codemirror/state that's older than what @codemirror/commands requires, a dev-tooling-only conflict; Obsidian itself supplies one consistent set of CodeMirror packages at runtime.)

Copy manifest.json and main.js into <vault>/.obsidian/plugins/sentence-capitalizer/, then enable the plugin in Obsidian's Community Plugins settings.

Tests

npm run test

Runs against a real CodeMirror EditorState/EditorView (jsdom), simulating actual keystroke-by-keystroke typing, Enter, and undo/redo, not just the pure decision logic in isolation, since most of the interesting bugs here were in how transactions and history interact.