base-embedding.ts•2.01 kB
// Interface definitions
export interface EmbeddingVector {
vector: number[];
dimension: number;
}
/**
* Abstract base class for embedding implementations
*/
export abstract class Embedding {
protected abstract maxTokens: number;
/**
* Preprocess text to ensure it's valid for embedding
* @param text Input text
* @returns Processed text
*/
protected preprocessText(text: string): string {
// Replace empty string with single space
if (text === '') {
return ' ';
}
// Simple character-based truncation (approximation)
// Each token is roughly 4 characters on average for English text
const maxChars = this.maxTokens * 4;
if (text.length > maxChars) {
return text.substring(0, maxChars);
}
return text;
}
/**
* Detect embedding dimension
* @param testText Test text for dimension detection
* @returns Embedding dimension
*/
abstract detectDimension(testText?: string): Promise<number>;
/**
* Preprocess array of texts
* @param texts Array of input texts
* @returns Array of processed texts
*/
protected preprocessTexts(texts: string[]): string[] {
return texts.map(text => this.preprocessText(text));
}
// Abstract methods that must be implemented by subclasses
/**
* Generate text embedding vector
* @param text Text content
* @returns Embedding vector
*/
abstract embed(text: string): Promise<EmbeddingVector>;
/**
* Generate text embedding vectors in batch
* @param texts Text array
* @returns Embedding vector array
*/
abstract embedBatch(texts: string[]): Promise<EmbeddingVector[]>;
/**
* Get embedding vector dimension
* @returns Vector dimension
*/
abstract getDimension(): number;
/**
* Get service provider name
* @returns Provider name
*/
abstract getProvider(): string;
}