obsidian-plugin-development

Obsidian Plugin Development

Overview

Write Obsidian plugin code that passes the ObsidianReviewBot automated review on first submission. All rules below are enforced by the bot via eslint-plugin-obsidianmd and @typescript-eslint. Violations labeled "Required" block merging.

When to Use

• Writing or editing TypeScript in an Obsidian plugin
• Preparing a plugin PR to obsidianmd/obsidian-releases
• Fixing ObsidianReviewBot violations
• Adding UI text, commands, settings tabs, or DOM manipulation

Quick Reference: Required Rules

1. Sentence Case for All UI Text

Every user-visible string: sentence case only.

// NO
'Block Settings'
'Add Block'
'Recent Files'

// YES
'Block settings'
'Add block'
'Recent files'

Applies to: Setting.setName(), Setting.setDesc(), createEl() text, button labels, modal titles, notices, menu items, tooltips. Proper nouns and acronyms (e.g. "API", "GitHub", "Obsidian") keep their casing.

2. No Inline Styles

Never assign element.style.* directly. Use CSS classes.

// NO
el.style.display = 'flex';
el.style.transform = 'scale(0.9)';
el.style.opacity = '0';

// YES — use CSS classes
el.addClass('hp-flex-container');
el.toggleClass('hp-scaled', true);
el.toggleClass('hp-hidden', true);

// For dynamic CSS custom properties, use setCssProps or setCssStyles:
el.setCssStyles({ '--my-var': value });

Flagged properties include: display, transform, opacity, width, height, margin, padding, cursor, fontSize, fontFamily, flexDirection, alignItems, flexShrink, borderRadius, backdropFilter, background, borderWidth, borderStyle, transition, gridTemplateRows, transformOrigin, and all others.

3. No Unnecessary Type Assertions

Don't as Type when it doesn't change the type.

// NO — assertion is redundant with ?? fallback
draft.url as string ?? ''
draft.showDate as boolean ?? true

// YES
String(draft.url ?? '')
Boolean(draft.showDate ?? true)
// or just
(draft.url ?? '') as string   // assertion AFTER coalescing

4. Promises Must Be Handled

Every Promise must be: awaited, .catch()ed, .then() with rejection handler, or voided.

// NO
someAsyncFn();
this.app.vault.read(file).then(text => { ... });

// YES
await someAsyncFn();
void someAsyncFn();
this.app.vault.read(file).then(text => { ... }, err => console.error(err));
this.app.vault.read(file).then(text => { ... }).catch(console.error);

5. No Async Without Await

Remove async from methods that don't use await.

// NO
async onOpen() { this.render(); }

// YES
onOpen() { this.render(); }

6. No Promise Where Void Expected

Don't return a Promise in callbacks expecting void.

// NO — event callback expects void
this.registerEvent(this.app.vault.on('modify', async (file) => {
  await this.reload();
}));

// YES
this.registerEvent(this.app.vault.on('modify', (file) => {
  void this.reload();
}));

7. No Object Stringification

Ensure values won't stringify as [object Object].

// NO — if draft is Record<string,unknown>, draft.mode could be an object
`Value: ${draft.mode ?? 'default'}`

// YES
`Value: ${String(draft.mode ?? 'default')}`

8. Settings Headings: Use Setting API

Don't create HTML headings. Use Setting.setHeading().

// NO
contentEl.createEl('h2', { text: 'My settings' });

// YES
new Setting(contentEl).setName('My settings').setHeading();

9. No Detach Leaves in onunload

Obsidian handles leaf cleanup. Detaching resets user's layout.

// NO
onunload() {
  this.app.workspace.detachLeavesOfType(VIEW_TYPE);
}

// YES
onunload() {
  // Obsidian cleans up leaves automatically
}

10. No TFile/TFolder Cast

Use instanceof instead of type casting.

// NO
const file = abstractFile as TFile;

// YES
if (abstractFile instanceof TFile) { ... }

11. No Forbidden DOM Elements

Don't create <style> or <link> elements dynamically.

12. No Plugin as Component

Don't pass this (plugin) to MarkdownRenderer.render(). Use a Component instance.

// NO
MarkdownRenderer.render(this.app, md, el, '', this);

// YES — use a Component subclass or this view/block
MarkdownRenderer.render(this.app, md, el, '', this.component);

13. No View References in Plugin

Don't store view references in plugin properties (memory leak).

14. Use Vault.configDir

Don't hardcode .obsidian. Use this.app.vault.configDir.

15. Platform Detection

Use Platform API, not navigator.userAgent.

// NO
if (navigator.userAgent.includes('Mac')) { ... }

// YES
import { Platform } from 'obsidian';
if (Platform.isMacOS) { ... }

16. No Regex Lookbehind

Lookbehinds break on some iOS versions. Avoid unless isDesktopOnly: true.

17. Commands

• No word "command" in command ID or name
• No plugin ID in command ID
• No plugin name in command name
• No default hotkeys

18. File Operations

• Use FileManager.trashFile() instead of Vault.trash()/Vault.delete()
• Don't iterate all files to find by path — use getAbstractFileByPath()
• Use normalizePath() for user-provided paths

19. No Sample/Template Code

Remove MyPlugin, SampleModal, template code from obsidian-sample-plugin.

20. Object.assign

Don't use Object.assign(this.settings, data) to mutate defaults.

21. Manifest & License

• manifest.json must have valid structure
• LICENSE must have correct copyright holder and current year
• Plugin ID: alphanumeric + dashes, no "obsidian", no "plugin" suffix
• Description: no "Obsidian", no "This plugin", must end with . ? ! )

Optional (Non-blocking)

• Remove unused variables and imports
• Use AbstractInputSuggest instead of copied TextInputSuggest

Additional Best Practices

Practice	Details
No innerHTML/outerHTML	Use createEl, setText, sanitizeHTMLToDom
Use requestUrl()	Instead of fetch() for network requests
CSS variables for theming	--background-secondary, --text-muted, etc.
Scope CSS	All plugin CSS scoped to plugin containers
Accessibility	aria-label on icon buttons, keyboard nav, focus indicators
Touch targets	Min 44x44px on mobile
Auto-cleanup	registerEvent(), registerInterval(), register()
No production logging	No console.log in onload()/onunload()

API Reference

See obsidian-api-reference.md in this skill directory for a condensed TypeScript API reference covering all key classes: Plugin, App, Vault, Workspace, MetadataCache, FileManager, Component, View, Modal, Setting, Menu, MarkdownRenderer, Platform, DOM helpers, and more.

For the full type definitions, read node_modules/obsidian/obsidian.d.ts in the project.

Running Checks Locally

npm install eslint-plugin-obsidianmd --save-dev

Configure ESLint with the plugin's recommended config. Run before submitting PR.

Common Mistakes

Mistake	Fix
Title Case in UI text	Sentence case everything
el.style.display = 'none'	el.addClass('hp-hidden')
as string ?? ''	String(x ?? '')
createEl('h2', ...) in modal	new Setting(el).setName(...).setHeading()
Async onOpen without await	Remove async keyword
Unhandled promise	Add void, await, or .catch()
detachLeavesOfType in onunload	Remove — Obsidian handles it
abstractFile as TFile	if (x instanceof TFile)