Add eslint rule to detect (some) side effects (that prevent tree shak…

…ing)

langchain/.eslintrc.cjs

@@ -11,9 +11,10 @@ module.exports = {
     project: "./tsconfig.json",
     sourceType: "module",
   },
-  plugins: ["@typescript-eslint"],
+  plugins: ["@typescript-eslint", "tree-shaking"],
   ignorePatterns: [".eslintrc.cjs", "create-entrypoints.js", "node_modules"],
   rules: {
+    "tree-shaking/no-side-effects-in-initialization": 2,
     "@typescript-eslint/explicit-module-boundary-types": 0,
     "@typescript-eslint/no-empty-function": 0,
     "@typescript-eslint/no-shadow": 0,

langchain/package.json

@@ -79,6 +79,7 @@
     "@types/uuid": "^9",
     "@typescript-eslint/eslint-plugin": "^5.51.0",
     "@typescript-eslint/parser": "^5.51.0",
+    "agadoo": "^3.0.0",
     "babel-jest": "^29.4.2",
     "cheerio": "^1.0.0-rc.12",
     "cohere-ai": "^5.0.2",
@@ -88,6 +89,7 @@
     "eslint-config-prettier": "^8.6.0",
     "eslint-plugin-import": "^2.27.5",
     "eslint-plugin-prettier": "^4.2.1",
+    "eslint-plugin-tree-shaking": "^1.10.0",
     "hnswlib-node": "^1.4.2",
     "husky": "^8.0.3",
     "jest": "^29.4.2",
@@ -268,4 +270,4 @@
       "import": "./output_parsers.js"
     }
   }
-}
+}

langchain/src/agents/tests/.eslintrc

@@ -0,0 +1,5 @@
+{
+  "rules": {
+    "tree-shaking/no-side-effects-in-initialization": 0
+  }
+}

langchain/src/cache.ts

@@ -1,3 +1,4 @@
+/* eslint-disable tree-shaking/no-side-effects-in-initialization */
 import crypto from "node:crypto";
 import type { RedisClientType } from "redis";
 import { Generation } from "./schema/index.js";
@@ -24,12 +25,14 @@ export abstract class BaseCache<T = Generation[]> {
   abstract update(prompt: string, llmKey: string, value: T): Promise<void>;
 }
 
+const GLOBAL_MAP = new Map();
+
 export class InMemoryCache<T = Generation[]> extends BaseCache<T> {
   #cache: Map<string, T>;
 
-  constructor() {
+  constructor(map?: Map<string, T>) {
     super();
-    this.#cache = new Map();
+    this.#cache = map ?? new Map();
   }
 
   lookup(prompt: string, llmKey: string): Promise<T | null> {
@@ -41,6 +44,10 @@ export class InMemoryCache<T = Generation[]> extends BaseCache<T> {
   async update(prompt: string, llmKey: string, value: T): Promise<void> {
     this.#cache.set(getCacheKey(prompt, llmKey), value);
   }
+
+  static global(): InMemoryCache {
+    return new InMemoryCache(GLOBAL_MAP);
+  }
 }
 
 /**

langchain/src/callbacks/tests/.eslintrc

@@ -0,0 +1,5 @@
+{
+  "rules": {
+    "tree-shaking/no-side-effects-in-initialization": 0
+  }
+}

langchain/src/chains/chat_vector_db_chain.ts

@@ -22,17 +22,13 @@ Chat History:
 {chat_history}
 Follow Up Input: {question}
 Standalone question:`;
-const question_generator_prompt = PromptTemplate.fromTemplate(
-  question_generator_template
-);
 
 const qa_template = `Use the following pieces of context to answer the question at the end. If you don't know the answer, just say that you don't know, don't try to make up an answer.
 
 {context}
 
 Question: {question}
 Helpful Answer:`;
-const qa_prompt = PromptTemplate.fromTemplate(qa_template);
 
 export interface ChatVectorDBQAChainInput {
   vectorstore: VectorStore;
@@ -189,9 +185,11 @@ export class ChatVectorDBQAChain
       returnSourceDocuments?: boolean;
     }
   ): ChatVectorDBQAChain {
-    const qaChain = loadQAStuffChain(llm, { prompt: qa_prompt });
+    const qaChain = loadQAStuffChain(llm, {
+      prompt: PromptTemplate.fromTemplate(qa_template),
+    });
     const questionGeneratorChain = new LLMChain({
-      prompt: question_generator_prompt,
+      prompt: PromptTemplate.fromTemplate(question_generator_template),
       llm,
     });
     const instance = new this({

langchain/src/chains/conversation.ts

@@ -11,11 +11,6 @@ Current conversation:
 Human: {input}
 AI:`;
 
-const defaultPrompt = new PromptTemplate({
-  template: defaultTemplate,
-  inputVariables: ["history", "input"],
-});
-
 export class ConversationChain extends LLMChain {
   constructor(fields: {
     llm: BaseLanguageModel;
@@ -24,7 +19,12 @@ export class ConversationChain extends LLMChain {
     memory?: BaseMemory;
   }) {
     super({
-      prompt: fields.prompt ?? defaultPrompt,
+      prompt:
+        fields.prompt ??
+        new PromptTemplate({
+          template: defaultTemplate,
+          inputVariables: ["history", "input"],
+        }),
       llm: fields.llm,
       outputKey: fields.outputKey ?? "response",
     });

langchain/src/chains/llm_chain.ts

@@ -129,11 +129,6 @@ Current conversation:
 Human: {input}
 AI:`;
 
-const defaultPrompt = new PromptTemplate({
-  template: defaultTemplate,
-  inputVariables: ["history", "input"],
-});
-
 export class ConversationChain extends LLMChain {
   constructor(fields: {
     llm: BaseLanguageModel;
@@ -142,7 +137,12 @@ export class ConversationChain extends LLMChain {
     memory?: BaseMemory;
   }) {
     super({
-      prompt: fields.prompt ?? defaultPrompt,
+      prompt:
+        fields.prompt ??
+        new PromptTemplate({
+          template: defaultTemplate,
+          inputVariables: ["history", "input"],
+        }),
       llm: fields.llm,
       outputKey: fields.outputKey ?? "response",
     });

langchain/src/chains/question_answering/tests/.eslintrc

@@ -0,0 +1,5 @@
+{
+  "rules": {
+    "tree-shaking/no-side-effects-in-initialization": 0
+  }
+}

langchain/src/chains/summarization/tests/.eslintrc

@@ -0,0 +1,5 @@
+{
+  "rules": {
+    "tree-shaking/no-side-effects-in-initialization": 0
+  }
+}

langchain/src/chains/tests/.eslintrc

@@ -0,0 +1,5 @@
+{
+  "rules": {
+    "tree-shaking/no-side-effects-in-initialization": 0
+  }
+}

langchain/src/chat_models/tests/.eslintrc

@@ -0,0 +1,5 @@
+{
+  "rules": {
+    "tree-shaking/no-side-effects-in-initialization": 0
+  }
+}

langchain/src/document_loaders/tests/.eslintrc

@@ -0,0 +1,5 @@
+{
+  "rules": {
+    "tree-shaking/no-side-effects-in-initialization": 0
+  }
+}

langchain/src/embeddings/tests/.eslintrc

@@ -0,0 +1,5 @@
+{
+  "rules": {
+    "tree-shaking/no-side-effects-in-initialization": 0
+  }
+}

langchain/src/llms/base.ts

@@ -8,8 +8,6 @@ import {
   BaseLanguageModelParams,
 } from "../base_language/index.js";
 
-const GLOBAL_CACHE: BaseCache = new InMemoryCache();
-
 export type SerializedLLM = {
   _model: string;
   _type: string;
@@ -45,7 +43,7 @@ export abstract class BaseLLM extends BaseLanguageModel {
     if (cache instanceof BaseCache) {
       this.cache = cache;
     } else if (cache) {
-      this.cache = GLOBAL_CACHE;
+      this.cache = InMemoryCache.global();
     } else {
       this.cache = undefined;
     }

langchain/src/llms/tests/.eslintrc

@@ -0,0 +1,5 @@
+{
+  "rules": {
+    "tree-shaking/no-side-effects-in-initialization": 0
+  }
+}

langchain/src/memory/tests/.eslintrc

@@ -0,0 +1,5 @@
+{
+  "rules": {
+    "tree-shaking/no-side-effects-in-initialization": 0
+  }
+}

langchain/src/output_parsers/tests/.eslintrc

@@ -0,0 +1,5 @@
+{
+  "rules": {
+    "tree-shaking/no-side-effects-in-initialization": 0
+  }
+}

langchain/src/prompts/tests/.eslintrc

@@ -0,0 +1,5 @@
+{
+  "rules": {
+    "tree-shaking/no-side-effects-in-initialization": 0
+  }
+}

langchain/src/sql_db.ts

@@ -1,4 +1,4 @@
-import { DataSource, DataSourceOptions } from "typeorm";
+import type { DataSource as DataSourceT, DataSourceOptions } from "typeorm";
 import {
   generateTableInfoFromTables,
   getTableAndColumnsName,
@@ -16,7 +16,7 @@ export class SqlDatabase
 {
   appDataSourceOptions: DataSourceOptions;
 
-  appDataSource: DataSource;
+  appDataSource: DataSourceT;
 
   allTables: Array<SqlTable> = [];
 
@@ -62,6 +62,7 @@ export class SqlDatabase
   static async fromOptionsParams(
     fields: SqlDatabaseOptionsParams
   ): Promise<SqlDatabase> {
+    const { DataSource } = await import("typeorm");
     const dataSource = new DataSource(fields.appDataSourceOptions);
     return SqlDatabase.fromDataSourceParams({
       ...fields,

langchain/src/tests/.eslintrc

@@ -0,0 +1,5 @@
+{
+  "rules": {
+    "tree-shaking/no-side-effects-in-initialization": 0
+  }
+}

langchain/src/util/sql_utils.ts

@@ -1,4 +1,4 @@
-import { DataSource, DataSourceOptions } from "typeorm";
+import type { DataSource, DataSourceOptions } from "typeorm";
 
 interface RawResultTableAndColumn {
   table_name: string;

langchain/src/util/tests/.eslintrc

@@ -0,0 +1,5 @@
+{
+  "rules": {
+    "tree-shaking/no-side-effects-in-initialization": 0
+  }
+}

langchain/src/vectorstores/tests/.eslintrc

@@ -0,0 +1,5 @@
+{
+  "rules": {
+    "tree-shaking/no-side-effects-in-initialization": 0
+  }
+}