adam@Adams-MacBook-Air ~ % mkdir foo
adam@Adams-MacBook-Air ~ % cd foo 
adam@Adams-MacBook-Air foo % yarn add typescript-language-server
yarn add v1.22.19
info No lockfile found.
[1/4] 🔍  Resolving packages...
[2/4] 🚚  Fetching packages...
[3/4] 🔗  Linking dependencies...
[4/4] 🔨  Building fresh packages...

success Saved lockfile.
success Saved 30 new dependencies.
info Direct dependencies
└─ typescript-language-server@1.1.0
info All dependencies
├─ commander@9.4.0
├─ crypto-random-string@4.0.0
├─ find-up@6.3.0
├─ fs-extra@10.1.0
├─ graceful-fs@4.2.10
├─ is-stream@3.0.0
├─ isexe@2.0.0
├─ jsonfile@6.1.0
├─ locate-path@7.1.1
├─ lru-cache@6.0.0
├─ p-debounce@4.0.0
├─ p-limit@4.0.0
├─ p-locate@6.0.0
├─ path-exists@5.0.0
├─ pkg-up@4.0.0
├─ semver@7.3.7
├─ temp-dir@2.0.0
├─ tempy@3.0.0
├─ type-fest@2.18.1
├─ typescript-language-server@1.1.0
├─ unique-string@3.0.0
├─ vscode-jsonrpc@8.0.2
├─ vscode-languageserver-protocol@3.17.2
├─ vscode-languageserver-textdocument@1.0.5
├─ vscode-languageserver-types@3.17.2
├─ vscode-languageserver@8.0.2
├─ vscode-uri@3.0.3
├─ which@2.0.2
├─ yallist@4.0.0
└─ yocto-queue@1.0.0
✨  Done in 0.91s.
adam@Adams-MacBook-Air foo % ls
node_modules	package.json	yarn.lock
adam@Adams-MacBook-Air foo % ./node_modules/.bin/typescript-language-server 
node:internal/errors:477
    ErrorCaptureStackTrace(err);
    ^

Error [ERR_MODULE_NOT_FOUND]: Cannot find package 'deepmerge' imported from /Users/adam/foo/node_modules/typescript-language-server/lib/configuration-manager.js
    at new NodeError (node:internal/errors:387:5)
    at packageResolve (node:internal/modules/esm/resolve:951:9)
    at moduleResolve (node:internal/modules/esm/resolve:1000:20)
    at defaultResolve (node:internal/modules/esm/resolve:1214:11)
    at nextResolve (node:internal/modules/esm/loader:165:28)
    at ESMLoader.resolve (node:internal/modules/esm/loader:844:30)
    at ESMLoader.getModuleJob (node:internal/modules/esm/loader:431:18)
    at ModuleWrap.<anonymous> (node:internal/modules/esm/module_job:76:40)
    at link (node:internal/modules/esm/module_job:75:36) {
  code: 'ERR_MODULE_NOT_FOUND'
}
adam@Adams-MacBook-Air foo %