Remove instanceof checks to support deno on supabase

langchain/.eslintrc.cjs

@@ -11,7 +11,7 @@ module.exports = {
     project: "./tsconfig.json",
     sourceType: "module",
   },
-  plugins: ["@typescript-eslint", "tree-shaking"],
+  plugins: ["@typescript-eslint", "tree-shaking", "no-instanceof"],
   ignorePatterns: [
     ".eslintrc.cjs",
     "scripts",
@@ -44,6 +44,7 @@ module.exports = {
       },
     ],
     "no-process-env": 2,
+    "no-instanceof/no-instanceof": 2,
     "@typescript-eslint/explicit-module-boundary-types": 0,
     "@typescript-eslint/no-empty-function": 0,
     "@typescript-eslint/no-shadow": 0,

langchain/package.json

@@ -128,6 +128,7 @@
     "eslint-config-airbnb-base": "^15.0.0",
     "eslint-config-prettier": "^8.6.0",
     "eslint-plugin-import": "^2.27.5",
+    "eslint-plugin-no-instanceof": "^1.0.1",
     "eslint-plugin-prettier": "^4.2.1",
     "eslint-plugin-tree-shaking": "^1.10.0",
     "hnswlib-node": "^1.4.2",

langchain/src/agents/agent.ts

@@ -312,6 +312,8 @@ export abstract class Agent extends BaseSingleActionAgent {
 
         return { returnValues: { output: action.log }, log: action.log };
       } catch (err) {
+        // fine to use instanceof because we're in the same module
+        // eslint-disable-next-line no-instanceof/no-instanceof
         if (!(err instanceof ParseError)) {
           throw err;
         }

langchain/src/callbacks/utils.ts

@@ -40,6 +40,8 @@ export async function setTracerSession(
   callbackManager: CallbackManager = getCallbackManager()
 ) {
   for (const handler of callbackManager.handlers) {
+    // fine to use instanceof here because we're in the same package
+    // eslint-disable-next-line no-instanceof/no-instanceof
     if (handler instanceof LangChainTracer) {
       const sessionName = options?.sessionName;
       if (sessionName) {

langchain/src/chains/prompt_selector.ts

@@ -1,6 +1,7 @@
 import { BaseChatModel } from "../chat_models/base.js";
 import { BasePromptTemplate } from "../prompts/base.js";
 import { BaseLanguageModel } from "../base_language/index.js";
+import { BaseLLM } from "../llms/base.js";
 
 export abstract class BasePromptSelector {
   abstract getPrompt(llm: BaseLanguageModel): BasePromptTemplate;
@@ -37,10 +38,10 @@ export class ConditionalPromptSelector extends BasePromptSelector {
   }
 }
 
-export function isLLM(llm: BaseLanguageModel): llm is BaseLanguageModel {
-  return llm instanceof BaseLanguageModel;
+export function isLLM(llm: BaseLanguageModel): llm is BaseLLM {
+  return llm._modelType() === "base_llm";
 }
 
 export function isChatModel(llm: BaseLanguageModel): llm is BaseChatModel {
-  return llm instanceof BaseChatModel;
+  return llm._modelType() === "base_chat_model";
 }

langchain/src/llms/base.ts

@@ -32,7 +32,7 @@ export abstract class BaseLLM extends BaseLanguageModel {
 
   constructor({ cache, concurrency, ...rest }: BaseLLMParams) {
     super(concurrency ? { maxConcurrency: concurrency, ...rest } : rest);
-    if (cache instanceof BaseCache) {
+    if (typeof cache === "object") {
       this.cache = cache;
     } else if (cache) {
       this.cache = InMemoryCache.global();

langchain/src/memory/base.ts

@@ -1,10 +1,4 @@
-import {
-  BaseChatMessage,
-  HumanChatMessage,
-  AIChatMessage,
-  SystemChatMessage,
-  ChatMessage,
-} from "../schema/index.js";
+import { BaseChatMessage, ChatMessage } from "../schema/index.js";
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
 export type InputValues = Record<string, any>;
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
@@ -42,14 +36,14 @@ export function getBufferString(
   const string_messages: string[] = [];
   for (const m of messages) {
     let role: string;
-    if (m instanceof HumanChatMessage) {
+    if (m._getType() === "human") {
       role = human_prefix;
-    } else if (m instanceof AIChatMessage) {
+    } else if (m._getType() === "ai") {
       role = ai_prefix;
-    } else if (m instanceof SystemChatMessage) {
+    } else if (m._getType() === "system") {
       role = "System";
-    } else if (m instanceof ChatMessage) {
-      role = m.role;
+    } else if (m._getType() === "generic") {
+      role = (m as ChatMessage).role;
     } else {
       throw new Error(`Got unsupported message type: ${m}`);
     }

langchain/src/output_parsers/fix.ts

@@ -37,6 +37,7 @@ export class OutputFixingParser extends BaseOutputParser {
     try {
       return await this.parser.parse(completion);
     } catch (e) {
+      // eslint-disable-next-line no-instanceof/no-instanceof
       if (e instanceof OutputParserException) {
         const result = await this.retryChain.call({
           instructions: this.parser.getFormatInstructions(),

langchain/src/output_parsers/structured.ts

@@ -1,3 +1,4 @@
+/* eslint-disable no-instanceof/no-instanceof */
 import { z } from "zod";
 
 import { BaseOutputParser, OutputParserException } from "../schema/index.js";

yarn.lock

@@ -7989,6 +7989,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"eslint-plugin-no-instanceof@npm:^1.0.1":
+  version: 1.0.1
+  resolution: "eslint-plugin-no-instanceof@npm:1.0.1"
+  checksum: 80b152b13869fd88debb9d387ca225dd18e5a75fe33f9510e71a65070a4862bfca5a57dc42b508259d8150f318312bf26c09e570874c2871bf0f59c4b745cfe5
+  languageName: node
+  linkType: hard
+
 "eslint-plugin-prettier@npm:^4.2.1":
   version: 4.2.1
   resolution: "eslint-plugin-prettier@npm:4.2.1"
@@ -11468,6 +11475,7 @@ __metadata:
     eslint-config-airbnb-base: ^15.0.0
     eslint-config-prettier: ^8.6.0
     eslint-plugin-import: ^2.27.5
+    eslint-plugin-no-instanceof: ^1.0.1
     eslint-plugin-prettier: ^4.2.1
     eslint-plugin-tree-shaking: ^1.10.0
     exponential-backoff: ^3.1.0