Overview The Schema module defines the foundational data structures used throughout LlamaIndex.TS, including documents, nodes, relationships, and response types.
BaseNode Base class for all node types in LlamaIndex.
import { BaseNode } from "@llamaindex/core/schema" ;
Properties Unique identifier for the node (auto-generated if not provided)
Vector embedding of the node content
Arbitrary metadata associated with the node
excludedEmbedMetadataKeys
Metadata keys to exclude when generating embeddings
Metadata keys to exclude when sending to LLM
relationships
Record<NodeRelationship, RelatedNodeInfo>
Relationships to other nodes (parent, child, next, previous)
Methods Get node content with metadata based on mode getContent ( metadataMode : MetadataMode ): string
Mode: ALL, EMBED, LLM, or NONE
Convert node to RelatedNodeInfo for relationship storage asRelatedNodeInfo (): RelatedNodeInfo
TextNode Node representing a chunk of text, extending BaseNode.
import { TextNode } from "@llamaindex/core/schema" ;
Additional Properties The text content of the node
Start character index in the parent document
End character index in the parent document
Template for formatting text with metadata
Template for formatting metadata
Example const node = new TextNode ({ text: "LlamaIndex is a data framework for LLM applications." , metadata: { source: "documentation" , page: 1 } }); console . log ( node . id_ ); // Auto-generated UUID console . log ( node . getContent ( MetadataMode . ALL )); // Text with metadata
Document Represents a complete document, extends TextNode.
import { Document } from "@llamaindex/core/schema" ;
Additional Properties Document ID (used as doc_id in chunks)
Example const document = new Document ({ text: "Full document text..." , metadata: { title: "My Document" , author: "John Doe" , date: "2024-01-01" } });
NodeWithScore Node with a relevance score, used in retrieval results.
interface NodeWithScore < T extends BaseNode = BaseNode > { node : T ; score ?: number ; }
Relevance score (typically 0-1, higher is more relevant)
EngineResponse Response from query or chat engines.
import { EngineResponse } from "@llamaindex/core/schema" ;
Properties The generated response text
Source nodes used to generate the response
Additional metadata about the response
Example const response : EngineResponse = { response: "LlamaIndex is a data framework..." , sourceNodes: [ { node: textNode , score: 0.95 } ], metadata: { totalTokens: 150 } };
Node Relationships enum NodeRelationship { SOURCE = "source" , PREVIOUS = "previous" , NEXT = "next" , PARENT = "parent" , CHILD = "child" }
Example: Node with Relationships const parentDoc = new Document ({ text: "Parent document" }); const childNode = new TextNode ({ text: "Child chunk" , relationships: { [NodeRelationship. SOURCE ]: parentDoc . asRelatedNodeInfo () } });
enum MetadataMode { ALL = "all" , // Include all metadata EMBED = "embed" , // For embedding (excludes excludedEmbedMetadataKeys) LLM = "llm" , // For LLM (excludes excludedLlmMetadataKeys) NONE = "none" // No metadata }
Base class for components that transform nodes (e.g., embeddings, parsers).
abstract class TransformComponent < T > { abstract transform ( nodes : BaseNode [], options ?: any ) : T ; }
Example import { TransformComponent } from "@llamaindex/core/schema" ; class MyTransform extends TransformComponent < Promise < BaseNode []>> { async transform ( nodes : BaseNode []) : Promise < BaseNode []> { // Transform nodes return nodes . map ( node => { // Add custom metadata node . metadata . processed = true ; return node ; }); } }
FileReader Base interface for reading files into documents.
interface BaseReader < T = any > { loadData ( ... args : any []) : Promise < Document []>; }
Example import { SimpleDirectoryReader } from "llamaindex" ; const reader = new SimpleDirectoryReader (); const documents = await reader . loadData ( "./docs" );
Output Parsers interface BaseOutputParser < T > { parse ( output : string ) : T ; format ( prompt : string ) : string ; }
Output parsers transform LLM text outputs into structured data.