Entities

Entity System

Trilium's data model is based on five core entities:

graph TD
    Note[Note
BNote]
    Branch[Branch
BBranch]
    Attribute[Attribute
BAttribute]
    Revision[Revision
BRevision]
    Attachment[Attachment
BAttachment]
    
    Note -->|linked by| Branch
    Note -.->|metadata| Attribute
    Branch -->|creates| Revision
    Note -->|has| Attachment
    
    style Note fill:#e1f5ff
    style Branch fill:#fff4e1
    style Attribute fill:#ffe1f5
    style Revision fill:#f5ffe1
    style Attachment fill:#ffe1e1

Entity Definitions

1. BNote (apps/server/src/becca/entities/bnote.ts)

• Represents a note with title, content, and metadata
• Type can be: text, code, file, image, canvas, mermaid, etc.
• Contains content via blob reference
• Can be protected (encrypted)
• Has creation and modification timestamps

2. BBranch (apps/server/src/becca/entities/bbranch.ts)

• Represents parent-child relationship between notes
• Enables note cloning (multiple parents)
• Contains positioning information
• Has optional prefix for customization
• Tracks expansion state in tree

3. BAttribute (apps/server/src/becca/entities/battribute.ts)

• Key-value metadata attached to notes
• Two types: labels (tags) and relations (links)
• Can be inheritable to child notes
• Used for search, organization, and scripting
• Supports promoted attributes (displayed prominently)

4. BRevision (apps/server/src/becca/entities/brevision.ts)

• Stores historical versions of note content
• Automatic versioning on edits
• Retains title, type, and content
• Enables note history browsing and restoration

5. BAttachment (apps/server/src/becca/entities/battachment.ts)

• File attachments linked to notes
• Has owner (note), role, and mime type
• Content stored in blobs
• Can be protected (encrypted)

6. BBlob (apps/server/src/becca/entities/bblob.ts)

• Binary large object storage
• Stores actual note content and attachments
• Referenced by notes, revisions, and attachments
• Supports encryption for protected content

Widget-Based UI

The frontend uses a widget system for modular, reusable UI components.

Located at: apps/client/src/widgets/

// Widget Hierarchy
BasicWidget
├── NoteContextAwareWidget (responds to note changes)
│   ├── RightPanelWidget (displayed in right sidebar)
│   └── Type-specific widgets
├── Container widgets (tabs, ribbons, etc.)
└── Specialized widgets (search, calendar, etc.)

Base Classes:

1. BasicWidget (basic_widget.ts)
   • Base class for all UI components
   • Lifecycle: construction → rendering → events → destruction
   • Handles DOM manipulation
   • Event subscription management
   • Child widget management
2. NoteContextAwareWidget (note_context_aware_widget.ts)
   • Extends BasicWidget
   • Automatically updates when active note changes
   • Accesses current note context
   • Used for note-dependent UI
3. RightPanelWidget
   • Widgets displayed in right sidebar
   • Collapsible sections
   • Context-specific tools and information

Type-Specific Widgets:

Each note type has a dedicated widget, which are located in apps/client/src/widgets/type_widgets.