agsamantha/node_modules/langchain/dist/memory/entity_memory.js

import { getPromptInputKey, } from "@langchain/core/memory";
import { getBufferString } from "@langchain/core/messages";
import { InMemoryEntityStore } from "./stores/entity/in_memory.js";
import { LLMChain } from "../chains/llm_chain.js";
import { ENTITY_EXTRACTION_PROMPT, ENTITY_SUMMARIZATION_PROMPT, } from "./prompt.js";
import { BaseChatMemory } from "./chat_memory.js";
// Entity extractor & summarizer to memory.
/**
 * Class for managing entity extraction and summarization to memory in
 * chatbot applications. Extends the BaseChatMemory class and implements
 * the EntityMemoryInput interface.
 * @example
 * ```typescript
 * const memory = new EntityMemory({
 *   llm: new ChatOpenAI({ temperature: 0 }),
 *   chatHistoryKey: "history",
 *   entitiesKey: "entities",
 * });
 * const model = new ChatOpenAI({ temperature: 0.9 });
 * const chain = new LLMChain({
 *   llm: model,
 *   prompt: ENTITY_MEMORY_CONVERSATION_TEMPLATE,
 *   memory,
 * });
 *
 * const res1 = await chain.call({ input: "Hi! I'm Jim." });
 * console.log({
 *   res1,
 *   memory: await memory.loadMemoryVariables({ input: "Who is Jim?" }),
 * });
 *
 * const res2 = await chain.call({
 *   input: "I work in construction. What about you?",
 * });
 * console.log({
 *   res2,
 *   memory: await memory.loadMemoryVariables({ input: "Who is Jim?" }),
 * });
 *
 * ```
 */
export class EntityMemory extends BaseChatMemory {
    constructor(fields) {
        super({
            chatHistory: fields.chatHistory,
            returnMessages: fields.returnMessages ?? false,
            inputKey: fields.inputKey,
            outputKey: fields.outputKey,
        });
        Object.defineProperty(this, "entityExtractionChain", {
            enumerable: true,
            configurable: true,
            writable: true,
            value: void 0
        });
        Object.defineProperty(this, "entitySummarizationChain", {
            enumerable: true,
            configurable: true,
            writable: true,
            value: void 0
        });
        Object.defineProperty(this, "entityStore", {
            enumerable: true,
            configurable: true,
            writable: true,
            value: void 0
        });
        Object.defineProperty(this, "entityCache", {
            enumerable: true,
            configurable: true,
            writable: true,
            value: []
        });
        Object.defineProperty(this, "k", {
            enumerable: true,
            configurable: true,
            writable: true,
            value: 3
        });
        Object.defineProperty(this, "chatHistoryKey", {
            enumerable: true,
            configurable: true,
            writable: true,
            value: "history"
        });
        Object.defineProperty(this, "llm", {
            enumerable: true,
            configurable: true,
            writable: true,
            value: void 0
        });
        Object.defineProperty(this, "entitiesKey", {
            enumerable: true,
            configurable: true,
            writable: true,
            value: "entities"
        });
        Object.defineProperty(this, "humanPrefix", {
            enumerable: true,
            configurable: true,
            writable: true,
            value: void 0
        });
        Object.defineProperty(this, "aiPrefix", {
            enumerable: true,
            configurable: true,
            writable: true,
            value: void 0
        });
        this.llm = fields.llm;
        this.humanPrefix = fields.humanPrefix;
        this.aiPrefix = fields.aiPrefix;
        this.chatHistoryKey = fields.chatHistoryKey ?? this.chatHistoryKey;
        this.entitiesKey = fields.entitiesKey ?? this.entitiesKey;
        this.entityExtractionChain = new LLMChain({
            llm: this.llm,
            prompt: fields.entityExtractionPrompt ?? ENTITY_EXTRACTION_PROMPT,
        });
        this.entitySummarizationChain = new LLMChain({
            llm: this.llm,
            prompt: fields.entitySummarizationPrompt ?? ENTITY_SUMMARIZATION_PROMPT,
        });
        this.entityStore = fields.entityStore ?? new InMemoryEntityStore();
        this.entityCache = fields.entityCache ?? this.entityCache;
        this.k = fields.k ?? this.k;
    }
    get memoryKeys() {
        return [this.chatHistoryKey];
    }
    // Will always return list of memory variables.
    get memoryVariables() {
        return [this.entitiesKey, this.chatHistoryKey];
    }
    // Return history buffer.
    /**
     * Method to load memory variables and perform entity extraction.
     * @param inputs Input values for the method.
     * @returns Promise resolving to an object containing memory variables.
     */
    async loadMemoryVariables(inputs) {
        const promptInputKey = this.inputKey ?? getPromptInputKey(inputs, this.memoryVariables);
        const messages = await this.chatHistory.getMessages();
        const serializedMessages = getBufferString(messages.slice(-this.k * 2), this.humanPrefix, this.aiPrefix);
        const output = await this.entityExtractionChain.predict({
            history: serializedMessages,
            input: inputs[promptInputKey],
        });
        const entities = output.trim() === "NONE" ? [] : output.split(",").map((w) => w.trim());
        const entitySummaries = {};
        for (const entity of entities) {
            entitySummaries[entity] = await this.entityStore.get(entity, "No current information known.");
        }
        this.entityCache = [...entities];
        const buffer = this.returnMessages
            ? messages.slice(-this.k * 2)
            : serializedMessages;
        return {
            [this.chatHistoryKey]: buffer,
            [this.entitiesKey]: entitySummaries,
        };
    }
    // Save context from this conversation to buffer.
    /**
     * Method to save the context from a conversation to a buffer and perform
     * entity summarization.
     * @param inputs Input values for the method.
     * @param outputs Output values from the method.
     * @returns Promise resolving to void.
     */
    async saveContext(inputs, outputs) {
        await super.saveContext(inputs, outputs);
        const promptInputKey = this.inputKey ?? getPromptInputKey(inputs, this.memoryVariables);
        const messages = await this.chatHistory.getMessages();
        const serializedMessages = getBufferString(messages.slice(-this.k * 2), this.humanPrefix, this.aiPrefix);
        const inputData = inputs[promptInputKey];
        for (const entity of this.entityCache) {
            const existingSummary = await this.entityStore.get(entity, "No current information known.");
            const output = await this.entitySummarizationChain.predict({
                summary: existingSummary,
                entity,
                history: serializedMessages,
                input: inputData,
            });
            if (output.trim() !== "UNCHANGED") {
                await this.entityStore.set(entity, output.trim());
            }
        }
    }
    // Clear memory contents.
    /**
     * Method to clear the memory contents.
     * @returns Promise resolving to void.
     */
    async clear() {
        await super.clear();
        await this.entityStore.clear();
    }
}