FlexTree Efficient Tree-Structured Data Storage Library

Left-Right Value algorithm / query-first / no recursion

Efficient Queries

Based on the Left-Right Value algorithm, relationship queries such as descendants, ancestors, children, and siblings can all be completed in a single SQL statement—no recursion required. The deeper the tree, the greater the advantage.

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Concise API

Semantic method names cover the full lifecycle—CRUD, traversal, move, and export—so you never have to hand-write complex SQL.

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Full Type Safety

Built with TypeScript and full generics support—custom field names and types still get precise type hints.

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Transaction & Concurrency Safety

All operations inside a write share the same database transaction—any failure rolls back the whole batch; a concurrency read guard prevents reading intermediate left/right values.

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Multi-Database Support

The adapter pattern decouples database access—ships with SQLite, Prisma, and Bun SQLite adapters, supports multi-dialect SQL generation, and can be extended to any database.

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Verify & Repair

verify checks tree-structure integrity via pure SQL; repair rebuilds corrupted left/right values and levels.

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Flexible Customization

Supports custom key-field names and types, multiple trees in a single table (treeId supports both numbers and strings), singleton management, and lazy loading.

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Traversal & Export

forEach supports DFS/BFS traversal and can be interrupted at any time; toJson/toList export the tree as nested JSON or a flat list.

🌐 Translation Notice: This English documentation may lag behind the Chinese original. When in doubt, the Chinese version is the source of truth.