393 lines
14 KiB
JavaScript
393 lines
14 KiB
JavaScript
import { AIMessage, AIMessageChunk, ChatMessage, ChatMessageChunk, HumanMessageChunk, } from "@langchain/core/messages";
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import { BaseChatModel, } from "@langchain/core/language_models/chat_models";
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import Prem from "@premai/prem-sdk";
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import { getEnvironmentVariable } from "@langchain/core/utils/env";
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import { ChatGenerationChunk, } from "@langchain/core/outputs";
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function extractGenericMessageCustomRole(message) {
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if (message.role !== "assistant" && message.role !== "user") {
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console.warn(`Unknown message role: ${message.role}`);
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}
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return message.role;
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}
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export function messageToPremRole(message) {
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const type = message._getType();
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switch (type) {
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case "ai":
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return "assistant";
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case "human":
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return "user";
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case "generic": {
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if (!ChatMessage.isInstance(message))
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throw new Error("Invalid generic chat message");
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return extractGenericMessageCustomRole(message);
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}
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default:
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throw new Error(`Unknown message type: ${type}`);
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}
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}
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function convertMessagesToPremParams(messages) {
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return messages.map((message) => {
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if (typeof message.content !== "string") {
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throw new Error("Non string message content not supported");
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}
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return {
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role: messageToPremRole(message),
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content: message.content,
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name: message.name,
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function_call: message.additional_kwargs.function_call,
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};
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});
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}
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function premResponseToChatMessage(message) {
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switch (message.role) {
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case "assistant":
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return new AIMessage(message.content || "");
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default:
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return new ChatMessage(message.content || "", message.role ?? "unknown");
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}
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}
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function _convertDeltaToMessageChunk(
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// eslint-disable-next-line @typescript-eslint/no-explicit-any
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delta) {
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const { role } = delta;
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const content = delta.content ?? "";
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let additional_kwargs;
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if (delta.function_call) {
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additional_kwargs = {
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function_call: delta.function_call,
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};
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}
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else {
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additional_kwargs = {};
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}
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if (role === "user") {
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return new HumanMessageChunk({ content });
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}
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else if (role === "assistant") {
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return new AIMessageChunk({ content, additional_kwargs });
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}
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else {
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return new ChatMessageChunk({ content, role });
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}
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}
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/**
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* Integration with a chat model.
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*/
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export class ChatPrem extends BaseChatModel {
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// Used for tracing, replace with the same name as your class
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static lc_name() {
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return "ChatPrem";
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}
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/**
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* Replace with any secrets this class passes to `super`.
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* See {@link ../../langchain-cohere/src/chat_model.ts} for
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* an example.
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*/
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get lc_secrets() {
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return {
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apiKey: "PREM_API_KEY",
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};
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}
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get lc_aliases() {
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return {
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apiKey: "PREM_API_KEY",
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};
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}
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constructor(fields) {
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super(fields ?? {});
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Object.defineProperty(this, "client", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "apiKey", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "project_id", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "session_id", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "messages", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "model", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "system_prompt", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "frequency_penalty", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "logit_bias", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "max_tokens", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "n", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "presence_penalty", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "response_format", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "seed", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "stop", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "temperature", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "top_p", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "tools", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "user", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: void 0
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});
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Object.defineProperty(this, "streaming", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: false
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});
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Object.defineProperty(this, "lc_serializable", {
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enumerable: true,
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configurable: true,
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writable: true,
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value: true
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});
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const apiKey = fields?.apiKey ?? getEnvironmentVariable("PREM_API_KEY");
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if (!apiKey) {
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throw new Error(`Prem API key not found. Please set the PREM_API_KEY environment variable or provide the key into "apiKey"`);
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}
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const projectId = fields?.project_id ??
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parseInt(getEnvironmentVariable("PREM_PROJECT_ID") ?? "-1", 10);
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if (!projectId || projectId === -1 || typeof projectId !== "number") {
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throw new Error(`Prem project ID not found. Please set the PREM_PROJECT_ID environment variable or provide the key into "project_id"`);
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}
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this.client = new Prem({
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apiKey,
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});
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this.project_id = projectId;
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this.session_id = fields?.session_id ?? this.session_id;
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this.messages = fields?.messages ?? this.messages;
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this.model = fields?.model ?? this.model;
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this.system_prompt = fields?.system_prompt ?? this.system_prompt;
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this.frequency_penalty =
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fields?.frequency_penalty ?? this.frequency_penalty;
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this.logit_bias = fields?.logit_bias ?? this.logit_bias;
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this.max_tokens = fields?.max_tokens ?? this.max_tokens;
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this.n = fields?.n ?? this.n;
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this.presence_penalty = fields?.presence_penalty ?? this.presence_penalty;
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this.response_format = fields?.response_format ?? this.response_format;
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this.seed = fields?.seed ?? this.seed;
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this.stop = fields?.stop ?? this.stop;
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this.temperature = fields?.temperature ?? this.temperature;
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this.top_p = fields?.top_p ?? this.top_p;
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this.tools = fields?.tools ?? this.tools;
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this.user = fields?.user ?? this.user;
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this.streaming = fields?.streaming ?? this.streaming;
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}
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// Replace
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_llmType() {
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return "prem";
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}
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async completionWithRetry(request,
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// eslint-disable-next-line @typescript-eslint/no-explicit-any
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options) {
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return this.caller.call(async () => this.client.chat.completions.create(request, options));
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}
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invocationParams(options) {
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const params = super.invocationParams(options);
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return {
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...params,
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project_id: this.project_id,
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session_id: this.session_id,
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messages: this.messages,
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model: this.model,
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system_prompt: this.system_prompt,
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frequency_penalty: this.frequency_penalty,
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logit_bias: this.logit_bias,
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max_tokens: this.max_tokens,
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n: this.n,
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presence_penalty: this.presence_penalty,
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response_format: this.response_format,
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seed: this.seed,
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stop: this.stop,
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temperature: this.temperature,
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top_p: this.top_p,
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tools: this.tools,
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user: this.user,
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streaming: this.streaming,
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stream: this.streaming,
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};
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}
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/**
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* Implement to support streaming.
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* Should yield chunks iteratively.
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*/
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async *_streamResponseChunks(messages, options, runManager) {
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const params = this.invocationParams(options);
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const messagesMapped = convertMessagesToPremParams(messages);
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// All models have a built-in `this.caller` property for retries
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const stream = await this.caller.call(async () => this.completionWithRetry({
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...params,
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messages: messagesMapped,
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stream: true,
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}, params));
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for await (const data of stream) {
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const choice = data?.choices[0];
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if (!choice) {
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continue;
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}
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const chunk = new ChatGenerationChunk({
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message: _convertDeltaToMessageChunk(choice.delta ?? {}),
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text: choice.delta.content ?? "",
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generationInfo: {
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finishReason: choice.finish_reason,
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},
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});
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yield chunk;
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void runManager?.handleLLMNewToken(chunk.text ?? "");
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}
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if (options.signal?.aborted) {
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throw new Error("AbortError");
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}
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}
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/** @ignore */
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_combineLLMOutput() {
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return [];
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}
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async _generate(messages, options, runManager) {
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const tokenUsage = {};
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const params = this.invocationParams(options);
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const messagesMapped = convertMessagesToPremParams(messages);
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if (params.streaming) {
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const stream = this._streamResponseChunks(messages, options, runManager);
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const finalChunks = {};
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for await (const chunk of stream) {
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const index = chunk.generationInfo?.completion ?? 0;
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if (finalChunks[index] === undefined) {
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finalChunks[index] = chunk;
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}
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else {
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finalChunks[index] = finalChunks[index].concat(chunk);
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}
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}
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const generations = Object.entries(finalChunks)
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.sort(([aKey], [bKey]) => parseInt(aKey, 10) - parseInt(bKey, 10))
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.map(([_, value]) => value);
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return { generations, llmOutput: { estimatedTokenUsage: tokenUsage } };
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}
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else {
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const data = await this.completionWithRetry({
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...params,
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stream: false,
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messages: messagesMapped,
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}, {
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signal: options?.signal,
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});
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if ("usage" in data && data.usage) {
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const { completion_tokens: completionTokens, prompt_tokens: promptTokens, total_tokens: totalTokens, } = data.usage;
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if (completionTokens) {
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tokenUsage.completionTokens =
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(tokenUsage.completionTokens ?? 0) + completionTokens;
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}
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if (promptTokens) {
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tokenUsage.promptTokens =
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(tokenUsage.promptTokens ?? 0) + promptTokens;
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}
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if (totalTokens) {
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tokenUsage.totalTokens = (tokenUsage.totalTokens ?? 0) + totalTokens;
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}
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}
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const generations = [];
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if ("choices" in data && data.choices) {
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for (const part of data
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.choices) {
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const text = part.message?.content ?? "";
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const generation = {
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text,
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message: premResponseToChatMessage(part.message ?? { role: "assistant" }),
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};
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generation.generationInfo = {
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...(part.finish_reason
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? { finish_reason: part.finish_reason }
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: {}),
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...(part.logprobs ? { logprobs: part.logprobs } : {}),
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};
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generations.push(generation);
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}
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}
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return {
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generations,
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llmOutput: { tokenUsage },
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};
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}
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}
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}
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