Migrating Content Between Rich Text Editors: A Complete Guide

Migrating content between rich text editors is one of the most challenging tasks in web development. Each editor has its own document model, data structure, and feature set, making direct migration anything but straightforward. Whether you’re moving from Draft.js to Lexical, Slate to ProseMirror, or any other combination, this guide will help you understand the challenges and implement a successful migration strategy.

The Migration Challenge

Rich text editors store content in fundamentally different ways:

  • Draft.js uses an immutable state tree with entity references
  • Slate uses a mutable tree of plain objects
  • ProseMirror uses a schema-based immutable tree
  • Lexical uses an immutable tree with a plugin system
  • Quill uses a Delta format with operations
  • TinyMCE/CKEditor use HTML with custom attributes

This diversity means there’s no universal migration path. You need to understand both source and target formats deeply.

Understanding Document Models

Each rich text editor represents content differently. Understanding these differences is crucial for successful migration.

Draft.js: Entity-Based Model

Draft.js uses a two-part system: blocks (paragraphs, headings, lists) and entities (links, mentions, custom widgets). Blocks contain text with style ranges and entity references, while entities store the actual data.

Draft.js Structure:
┌─────────────────────────────────────────────────────────┐
│ ContentState                                           │
├─────────────────────────────────────────────────────────┤
│ EntityMap: { "0": { type: "LINK", data: {...} } }      │
│ BlockMap: {                                            │
│   "a1b2c3": {                                          │
│     text: "Hello world",                               │
│     type: "unstyled",                                  │
│     inlineStyleRanges: [{ offset: 0, length: 5,       │
│                          style: "BOLD" }],             │
│     entityRanges: [{ offset: 6, length: 5, key: 0 }]  │
│   }                                                    │
│ }                                                      │
└─────────────────────────────────────────────────────────┘

Key characteristics: Immutable state, entity references, style ranges with offsets.

Slate: Tree of Plain Objects

Slate represents documents as a tree of plain JavaScript objects. Each node can have a type, properties, and children. Formatting is stored as properties on text nodes.

Slate Structure:
┌─────────────────────────────────────────────────────────┐
│ Document Tree                                          │
├─────────────────────────────────────────────────────────┤
│ [                                                      │
│   {                                                    │
│     type: "paragraph",                                 │
│     children: [                                        │
│       { text: "Hello ", bold: true },                 │
│       { text: "world", link: "https://..." }          │
│     ]                                                  │
│   }                                                    │
│ ]                                                      │
└─────────────────────────────────────────────────────────┘

Key characteristics: Mutable tree, properties on text nodes, flexible structure.

Lexical: Immutable Tree with Plugins

Lexical uses an immutable tree structure similar to React state. Each node has a type, version, and specific properties. The editor state is immutable and updated through transactions.

Lexical Structure:
┌─────────────────────────────────────────────────────────┐
│ EditorState                                            │
├─────────────────────────────────────────────────────────┤
│ {                                                      │
│   root: {                                              │
│     type: "root",                                      │
│     children: [                                        │
│       {                                                │
│         type: "paragraph",                             │
│         children: [                                    │
│           { type: "text", text: "Hello ",             │
│             format: 1 },                              │
│           { type: "link", url: "...",                 │
│             children: [{ type: "text", text: "world" }]│
│           ]                                            │
│         ]                                              │
│       }                                                │
│     ]                                                  │
│   }                                                    │
│ }                                                      │
└─────────────────────────────────────────────────────────┘

Key characteristics: Immutable tree, versioned nodes, plugin-based extensions.

Migration Strategies

There are three main approaches to migrating content between rich text editors, each with different trade-offs.

1. HTML as Intermediate Format

The most common and safest approach is to convert both source and target formats to HTML as a common language. This works because HTML is well-understood and most editors can import/export it.

Migration Flow:
┌─────────────┐    ┌─────────────┐    ┌─────────────┐
│ Source      │───▶│ HTML        │───▶│ Target      │
│ Editor      │    │ (Common     │    │ Editor      │
│ Content     │    │  Language)  │    │ Content     │
└─────────────┘    └─────────────┘    └─────────────┘

When to use: When you need a quick solution or when both editors have good HTML support.

Pros: Works for most editors, HTML is well-understood, safer approach Cons: Can lose some advanced formatting, not all features translate perfectly

2. Direct Model Transformation

For better fidelity, transform directly between the document models. This requires deep understanding of both formats but preserves more features.

Migration Flow:
┌─────────────┐    ┌─────────────────┐    ┌─────────────┐
│ Source      │───▶│ Custom          │───▶│ Target      │
│ Model       │    │ Transformation  │    │ Model       │
│             │    │ Logic           │    │             │
└─────────────┘    └─────────────────┘    └─────────────┘

When to use: When you need maximum fidelity or when HTML conversion loses important features.

Pros: Better fidelity, preserves more features, more control Cons: More complex, requires deep understanding of both formats, harder to maintain

3. Feature-by-Feature Migration

Migrate features incrementally, starting with core text formatting and gradually adding more complex features. This allows you to validate each step and rollback if needed.

Progressive Migration:
┌─────────────┐    ┌─────────────┐    ┌─────────────┐    ┌─────────────┐
│ Basic Text  │───▶│ Formatting  │───▶│ Links &     │───▶│ Custom      │
│ & Paragraphs│    │ (Bold, etc.)│    │ Lists       │    │ Features    │
└─────────────┘    └─────────────┘    └─────────────┘    └─────────────┘

When to use: For large migrations where you want to minimize risk and validate each step.

Pros: Lower risk, easier to debug, can rollback individual features Cons: Takes longer, requires more planning, may need temporary workarounds

Common Migration Challenges

Migration between rich text editors isn’t just about moving data—it’s about translating concepts between different systems. Here are the most common challenges you’ll face.

1. Incompatible Features

Not all features exist in every editor, or they exist in fundamentally different ways. For example, Draft.js uses entities for mentions, while Slate uses custom elements.

Feature Mapping Challenge:
┌─────────────────┐         ┌─────────────────┐
│ Draft.js        │         │ Slate           │
│ Entities        │    ❌   │ Custom Elements │
│ - Mentions      │────────▶│ - Mentions      │
│ - Links         │         │ - Links         │
│ - Embeds        │         │ - Embeds        │
└─────────────────┘         └─────────────────┘

Solution: Create mapping tables that define how each feature should be translated, and implement fallbacks for unsupported features.

2. Nested Structures

Different editors represent hierarchical content (like nested lists) in completely different ways. Draft.js uses depth numbers, while Slate uses actual nested tree structures.

Nesting Differences:
Draft.js:                    Slate:
┌─────────────────┐         ┌─────────────────┐
│ List Item       │         │ ul              │
│ depth: 0        │         │ ├─ li           │
│ List Item       │         │ │  └─ "Level 1" │
│ depth: 1        │         │ └─ ul           │
│ List Item       │         │    └─ li        │
│ depth: 1        │         │       └─ "Level 2" │
└─────────────────┘         └─────────────────┘

Solution: Implement recursive transformation functions that understand the nesting patterns of both editors and can convert between them.

3. Custom Extensions

Each editor has its own way of extending functionality. Draft.js uses entities, Slate uses custom elements, and Lexical uses custom nodes. These don’t translate directly.

Extension Systems:
┌─────────────────┐    ┌─────────────────┐    ┌─────────────────┐
│ Draft.js        │    │ Slate           │    │ Lexical         │
│ Entities        │    │ Custom Elements │    │ Custom Nodes    │
│ ┌─────────────┐ │    │ ┌─────────────┐ │    │ ┌─────────────┐ │
│ │ type: WIDGET│ │    │ │ type: widget│ │    │ │ class Widget│ │
│ │ data: {...} │ │    │ │ props: {...}│ │    │ │ extends Node│ │
│ └─────────────┘ │    │ └─────────────┘ │    │ └─────────────┘ │
└─────────────────┘    └─────────────────┘    └─────────────────┘

Solution: Create custom transformation logic for each type of extension, or implement equivalent functionality in the target editor.

Risk Mitigation Strategies

Migration is inherently risky. Here are proven strategies to minimize risk and ensure successful migrations.

1. Validation and Testing

Never trust that your migration works—always validate the results. Create comprehensive tests that check text content, formatting, structure, and custom features.

Validation Process:
┌─────────────┐    ┌─────────────┐    ┌─────────────┐    ┌─────────────┐
│ Original    │───▶│ Migration   │───▶│ Validation  │───▶│ Report      │
│ Content     │    │ Process     │    │ Checks      │    │ Issues      │
└─────────────┘    └─────────────┘    └─────────────┘    └─────────────┘

What to validate:

  • Text content matches exactly
  • Formatting (bold, italic, etc.) is preserved
  • Structure (headings, lists, etc.) is correct
  • Custom features work as expected
  • No data loss or corruption

Testing strategy: Start with simple content, then gradually test more complex scenarios. Use a representative sample of your actual content.

2. Incremental Migration

Don’t migrate everything at once. Break the migration into phases that you can validate and rollback independently.

Phased Migration:
┌─────────────┐    ┌─────────────┐    ┌─────────────┐
│ Phase 1:    │───▶│ Phase 2:    │───▶│ Phase 3:    │
│ Read-only   │    │ Edit with   │    │ Full        │
│ Migration   │    │ Fallback    │    │ Migration   │
└─────────────┘    └─────────────┘    └─────────────┘

Phase 1: Migrate content to read-only format, validate everything works Phase 2: Enable editing with ability to fallback to original format Phase 3: Complete migration with full functionality

This approach lets you catch issues early and minimize user impact.

3. Rollback Strategy

Always maintain the ability to rollback. Store original content, migration metadata, and create rollback procedures.

Rollback Safety:
┌─────────────┐    ┌─────────────┐    ┌─────────────┐
│ Original    │    │ Migration   │    │ Rollback    │
│ Content     │◄───┤ Record      │───▶│ Procedure   │
│ (Backup)    │    │ (Metadata)  │    │ (If needed) │
└─────────────┘    └─────────────┘    └─────────────┘

What to store:

  • Original content in its native format
  • Migration timestamp and version
  • Migration parameters and settings
  • Validation results and any issues found

Rollback triggers: Data corruption, performance issues, user complaints, or validation failures.

Real-World Migration Examples

Let’s look at how these strategies work in practice with common migration scenarios.

Draft.js to Lexical Migration

This is a common migration path since Draft.js is older and Lexical is the newer Meta framework. The HTML intermediate approach works well here.

Draft.js → Lexical Migration:
┌─────────────┐    ┌─────────────┐    ┌─────────────┐
│ Draft.js    │───▶│ HTML        │───▶│ Lexical     │
│ Content     │    │ Export      │    │ Parse       │
│ State       │    │ (draft-js-  │    │ (lexical-   │
│             │    │  export-    │    │  html)      │
│             │    │  html)      │    │             │
└─────────────┘    └─────────────┘    └─────────────┘

Key considerations:

  • Draft.js entities need special handling in HTML export
  • Lexical’s HTML parser handles most standard HTML well
  • Custom entities may need custom transformation logic
  • Some Draft.js features don’t have direct Lexical equivalents

Common issues: Entity data loss, formatting differences, custom block handling

Slate to ProseMirror Migration

This migration requires direct model transformation since both editors have very different document models.

Slate → ProseMirror Migration:
┌─────────────┐    ┌─────────────────┐    ┌─────────────┐
│ Slate       │───▶│ Custom          │───▶│ ProseMirror │
│ Tree        │    │ Transformation  │    │ Document    │
│ (Objects)   │    │ Logic           │    │ (Schema-    │
│             │    │                 │    │  based)     │
└─────────────┘    └─────────────────┘    └─────────────┘

Key considerations:

  • Slate’s flexible structure vs ProseMirror’s strict schema
  • Different approaches to marks vs formatting
  • Custom elements need schema definition in ProseMirror
  • Selection and cursor handling is completely different

Common issues: Schema validation failures, custom element mapping, performance with large documents

Tools and Libraries

Several tools and libraries can help with migration, though you’ll often need to build custom solutions for complex scenarios.

Available Migration Libraries

HTML Export/Import Libraries:

  • draft-js-export-html: Converts Draft.js content to HTML
  • slate-html-serializer: Converts Slate documents to/from HTML
  • lexical-html: Lexical’s built-in HTML parsing utilities
  • prosemirror-model: Utilities for working with ProseMirror documents

Editor-Specific Tools:

  • draft-js-utils: Various Draft.js utilities including export functions
  • slate-plugins: Community plugins that can help with transformations
  • lexical-plugins: Official Lexical plugins for common features

Building Custom Migration Tools

For complex migrations, you’ll likely need to build custom tools. The key is to create a framework that can handle the specific transformation logic for your use case.

Custom Migration Framework:
┌─────────────┐    ┌─────────────┐    ┌─────────────┐
│ Parser      │───▶│ Transformer │───▶│ Serializer  │
│ (Source     │    │ (Custom     │    │ (Target     │
│  Format)    │    │  Logic)     │    │  Format)    │
└─────────────┘    └─────────────┘    └─────────────┘

Parser: Converts source format into a common intermediate representation Transformer: Applies custom logic to handle feature mapping and edge cases Serializer: Converts the intermediate representation to target format

This approach gives you maximum control and allows you to handle editor-specific quirks and custom features.

Performance Considerations

Large-scale migrations can be resource-intensive. Here are strategies to handle performance challenges.

Batch Processing

When migrating thousands of documents, process them in manageable batches to avoid memory issues and provide progress feedback.

Batch Processing Strategy:
┌─────────────┐    ┌─────────────┐    ┌─────────────┐
│ Content     │───▶│ Batch       │───▶│ Processed   │
│ Database    │    │ Processor   │    │ Results     │
│ (10,000     │    │ (100 items  │    │ (Validated  │
│  items)     │    │  per batch) │    │  & stored)  │
└─────────────┘    └─────────────┘    └─────────────┘

Benefits: Memory efficiency, progress tracking, error isolation, ability to resume interrupted migrations

Caching and Optimization

Cache migration results to avoid redundant work, especially when the same content might be migrated multiple times during testing.

Caching Strategy:
┌─────────────┐    ┌─────────────┐    ┌─────────────┐
│ Input       │───▶│ Cache       │───▶│ Migration   │
│ Content     │    │ Check       │    │ Result      │
│ Hash        │    │ (Hit/Miss)  │    │ (Cached or  │
│             │    │             │    │  Fresh)     │
└─────────────┘    └─────────────┘    └─────────────┘

When to cache: During development/testing, for repeated migrations, when content hasn’t changed

Cache invalidation: When source content changes, when migration logic updates, when target format changes

Best Practices

Successful migrations follow proven patterns. Here are the key practices that separate successful migrations from problematic ones.

1. Start Small and Validate

Begin with a representative sample of your content, not your entire dataset. This lets you validate your approach before committing to a full migration.

Validation Strategy:
┌─────────────┐    ┌─────────────┐    ┌─────────────┐
│ Sample      │───▶│ Migration   │───▶│ Validation  │
│ Content     │    │ Test        │    │ & Refinement│
│ (100-1000   │    │ (Small      │    │ (Fix issues │
│  items)     │    │  scale)     │    │  & retest)  │
└─────────────┘    └─────────────┘    └─────────────┘

What to test: Simple text, complex formatting, nested structures, custom elements, edge cases

Success criteria: All content migrates correctly, performance is acceptable, no data loss

2. Comprehensive Documentation

Document every aspect of your migration process. This helps with debugging, team handoffs, and future migrations.

Documentation Requirements:
┌─────────────┐    ┌─────────────┐    ┌─────────────┐
│ Migration   │    │ Process     │    │ Results     │
│ Plan        │───▶│ Logs        │───▶│ Analysis    │
│ (Strategy,  │    │ (Timing,    │    │ (Success    │
│  timeline)  │    │  errors)    │    │  rates)     │
└─────────────┘    └─────────────┘    └─────────────┘

What to document: Migration strategy, test results, error patterns, performance metrics, rollback procedures

3. Rollback Planning

Always have a rollback plan. This isn’t just about storing backups—it’s about having a clear procedure to revert if things go wrong.

Rollback Strategy:
┌─────────────┐    ┌─────────────┐    ┌─────────────┐
│ Backup      │    │ Monitoring  │    │ Rollback    │
│ Storage     │───▶│ (Health     │───▶│ Procedure   │
│ (Original   │    │  checks)    │    │ (If needed) │
│  content)   │    │             │    │             │
└─────────────┘    └─────────────┘    └─────────────┘

Rollback triggers: Data corruption, performance degradation, user complaints, validation failures

Rollback procedure: Clear steps to restore original content, notify stakeholders, investigate issues

Conclusion

Migrating between rich text editors is complex but manageable with the right approach. The key is to:

  1. Understand both document models deeply
  2. Use HTML as an intermediate format when possible
  3. Implement comprehensive validation
  4. Migrate incrementally with rollback capability
  5. Test thoroughly with representative content

Remember that perfect migration is often impossible—focus on preserving the most important content and formatting while being prepared to handle edge cases gracefully.

The migration process is as much about managing risk as it is about technical implementation. By following these strategies, you can successfully migrate your content while minimizing disruption to your users.

Resources

Happy migrating!