Typescript ignores package.json export maps

[paulmillr]

Does this issue occur when all extensions are disabled?: Yes

• VS Code Version: 1.90.1
• OS Version: macos 14.5

Steps to Reproduce:

1. mkdir meth && cd meth && npm init -y && npm i micro-eth-signer && touch a.mjs
2. Open a.mjs and enter import * as net from 'micro-eth-signer/net'; or any other module. VSCode would not see the module even though it's clearly specified in pkg.json
3. Doesn't matter which tsconfig is used, i've tried all options (moduleResolution, module, whatever)

I maintain many libraries and I export their functionality in sub-modules instead of importing everything into one big index.js file. This is useful and helps with tree-shaking. Seems like vscode doesn't support export maps in node.js.

[VSCodeTriageBot]

Thanks for creating this issue! It looks like you may be using an old version of VS Code, the latest stable release is 1.90.1. Please try upgrading to the latest version and checking whether this issue remains.

Happy Coding!

[paulmillr]

@VSCodeTriageBot upgraded to 1.90.1

[RyanCavanaugh]

What are you expecting to see? This is what I get:

[DanielRosenwasser]

Without any more info, I'll point out the following information about the package from https://arethetypeswrong.github.io/?p=micro-eth-signer%400.9.1

	"micro-eth-signer"	"micro-eth-signer/abi"	"micro-eth-signer/net"	"micro-eth-signer/rlp"	"micro-eth-signer/ssz"	"micro-eth-signer/tx"	"micro-eth-signer/utils"
node10	✅	✅	✅	✅	✅	✅	✅
node16 (from CJS)	✅ (CJS)	✅ (CJS)	✅ (CJS)	💀 Resolution failed	💀 Resolution failed	✅ (CJS)	✅ (CJS)
node16 (from ESM)	🎭 Masquerading as CJS	🎭 Masquerading as CJS	🎭 Masquerading as CJS	💀 Resolution failed	💀 Resolution failed	🎭 Masquerading as CJS	🎭 Masquerading as CJS
bundler	✅	✅	✅	💀 Resolution failed	💀 Resolution failed	✅	✅

Under node16, ESM files will think that you're trying to import a CJS file (because they resolve to a .d.ts file under a package.json that implies a CJS code). See here.

[paulmillr]

@DanielRosenwasser this looks very useful, thanks. I will fix "masquearading". RLP and SSZ modules are failing because of a typo from my end.

Here's another package of mine:

https://arethetypeswrong.github.io/?p=micro-key-producer%400.7.0

It says "💀 Resolution failed" for all node16. I assume this is simply because cjs files are located in lib subdir and node10 can't find it. So until node10 resolution is deprecated (unclear when that happens), we are forced to not use clean structure with "all files are in subdirs".

Now, the question related to the first post is: which module resolution does typescript currently enforce by default? Is it node10? I mean, for the situation when there is no "tsconfig", and a random JS file is checked.