Errors when loading @langchain/core/messages in a typescript ES module

[marc-weber1]

Checked other resources

• I added a very descriptive title to this issue.
• I searched the LangChain.js documentation with the integrated search.
• I used the GitHub search to find a similar question and didn't find it.
• I am sure that this is a bug in LangChain.js rather than my code.
• The bug is not resolved by updating to the latest stable version of LangChain (or the specific integration package).

Example Code

import { BaseMessage, ChatMessage } from '@langchain/core/messages';

tsconfig:

{
	"compilerOptions": {
		"module": "Node16",
		"target": "ES2022",
		"outDir": "out",
		"lib": [
			"ES2022",
			"dom"
		],
		"sourceMap": true,
		"rootDir": "src",
		"strict": true
	}
}

Error Message and Stack Trace (if applicable)

@langchain/core/messages.d.cts:
The current file is a CommonJS module whose imports will produce 'require' calls; however, the referenced file is an ECMAScript module and cannot be imported with 'require'. Consider writing a dynamic 'import("./dist/messages/index.js")' call instead.

Description

Trying to make a VSCode extension, but can't with the required settings and langchain's cjs dependencies.

System Info

langchain@0.1.25 | MIT | deps: 18 | versions: 255
Typescript bindings for langchain
https://github.com/langchain-ai/langchainjs/tree/main/langchain/

keywords: llm, ai, gpt3, chain, prompt, prompt engineering, chatgpt, machine learning, ml, openai, embeddings, vectorstores

dist
.tarball: https://registry.npmjs.org/langchain/-/langchain-0.1.25.tgz
.shasum: afd0faf2eadfb5e6e1d57bb3bbc5731918e62135
.integrity: sha512-sfEChvr4H2CklHdSByNBbytwBrFhgtA5kPOnwcBrxuXGg1iOaTzhVxQA0QcNcQucI3hZrsNbZjxGp+Can1ooZQ==
.unpackedSize: 4.0 MB

dependencies:
@anthropic-ai/sdk: ^0.9.1 js-tiktoken: ^1.0.7 openapi-types: ^12.1.3
@langchain/community: ~0.0.33 js-yaml: ^4.1.0 p-retry: 4
@langchain/core: ~0.1.36 jsonpointer: ^5.0.1 uuid: ^9.0.0
@langchain/openai: ~0.0.14 langchainhub: ~0.0.8 yaml: ^2.2.1
binary-extensions: ^2.2.0 langsmith: ~0.1.7 zod-to-json-schema: ^3.22.3
expr-eval: ^2.0.2 ml-distance: ^4.0.0 zod: ^3.22.4

maintainers:

• nfcampos nuno@boringbits.io
• jacoblee93 jacoblee93@gmail.com
• davidduong david@duong.cz
• hwchase17 hw.chase.17@gmail.com
• basproul braceasproul@gmail.com

dist-tags:
latest: 0.1.25 next: 0.1.19-rc.2

published 5 days ago by basproul braceasproul@gmail.com

Windows 10 Pro
npm v10.2.4
NodeJS v20.11.1

[dosubot]

Hey @marc-weber1! Long time no see in the digital corridors of GitHub issues. 🚀

Based on the information you've provided, it seems like you're encountering an issue with importing the '@langchain/core/messages' module in a TypeScript ES module while developing a VSCode extension with LangChain.js version 0.1.25. This issue could be related to the module and moduleResolution settings in your tsconfig.json file.

Given the context of your tsconfig.json, you have the module option set to "Node16" and the target option set to "ES2022". These settings are generally appropriate for working with ES modules in a Node.js environment. However, the error you're experiencing might stem from one of the following reasons:

1. ES Module Compatibility: If '@langchain/core/messages' or any of its dependencies are not fully compatible with ES module syntax or the specific module target you've set ("ES2022"), this could lead to import errors. This is especially relevant if the package or parts of it are expecting a CommonJS module system.

2. Node's Module Resolution: The "Node16" value for module is designed to align with Node.js's native ESM support, including subpath patterns and package exports. If '@langchain/core/messages' or its dependencies are not properly configured to support this resolution strategy, it could result in loading errors.

To troubleshoot and potentially resolve this issue, consider the following steps:

• Check Package Exports: Ensure that '@langchain/core/messages' and its dependencies are correctly exporting modules for ES2022. Look for the package.json files in these packages to see if they have an "exports" field that supports the module format you're using.

• Module Type Compatibility: Verify whether '@langchain/core/messages' is expected to be imported as an ES module or if it requires CommonJS-style imports. This can sometimes be determined by the documentation or by inspecting the package's package.json for clues such as the "type" field being set to "module" (for ES modules) or the presence of "main" and "exports" fields.

• Adjust tsconfig Settings: As a test, you might try changing the module and moduleResolution settings in your tsconfig.json to see if a different configuration resolves the issue. For instance, setting module to "CommonJS" temporarily could help determine if the issue is related to ES module compatibility.

• Dependencies and Node Version: Ensure that all dependencies are up to date and that you're using a version of Node.js that fully supports the features and module resolution strategy you're employing.

Without specific error messages or more detailed information about how you're attempting to import '@langchain/core/messages', these suggestions are based on common issues related to module resolution and compatibility in TypeScript projects targeting ES modules in a Node.js environment.

Regarding similar issues in the langchainjs repository, there are several open and closed issues that seem to be related to your problem. The most relevant one is Unable to import anything, which is still open and was last updated on March 02, 2024. The suggested solutions in this issue include reinstalling langchainjs, checking the LangChain version, and updating the next.config.js. However, these solutions have received mixed reactions and it appears that a definitive solution has not been reached in the discussion.

I hope this information helps you in resolving the issue. If you need further assistance, please provide more details about the error messages you're receiving and how you're attempting to import '@langchain/core/messages'.

Sources

• Unable to import anything
• langchain in commonjs come up a error
• Unable to get langchain running with typescript/esbuild
• Issue importing submodules using es6 module import from documentation
• langchain-core/tsconfig.json
• langchain-core/src/messages/index.ts

About Dosu

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[jacoblee93]

Hey @marc-weber1, can you share your package.json file too?

[marc-weber1]

https://github.com/marc-weber1/langchain-vscode/blob/master/package.json

entire source code is on github, master branch as is should reproduce the error, may need vscode installed

[jacoblee93]

Sat"type": "module" in package JSON or use require

https://blog.logrocket.com/commonjs-vs-es-modules-node-js/

[marc-weber1]

BaseMessage and ChatMessage are types, and I can't convert a VSCode extension to an ES6 module; How am I supposed to import types with a require statement?

[marc-weber1]

microsoft/vscode#201935 - looks like they will fix this soon, but maybe include some documentation about either CommonJS not being supported or how to use it

[jacoblee93]

Oh hmm interesting. How do people usually require types in CJS? Haven't worked with it in a long time.

Would something like this work?

const { ChatPromptTemplate, LengthBasedExampleSelectorInput } = await import("@langchain/core/prompts");