Missing module in Javascript but not in Typescript

I'm coding a vscode extension following the guide and I came accross an import problem in my server.ts file. Here is the file tree:

test
 ┣ client
 ┃ ┣ out
 ┃ ┣ src
 ┃ ┃ ┗ index.ts
 ┃ ┣ package-lock.json
 ┃ ┣ package.json
 ┃ ┗ tsconfig.json
 ┣ server
 ┃ ┣ out
 ┃ ┣ src
 ┃ ┃ ┣ completions.ts
 ┃ ┃ ┣ parser.ts
 ┃ ┃ ┗ server.ts
 ┃ ┣ package-lock.json
 ┃ ┣ package.json
 ┃ ┣ tsconfig.json
 ┃ ┗ yarn.lock
 ┣ package.json
 ┗ tsconfig.json

Which is the same structrure as the extension sample provided by Microsoft.

However, in server.ts, I'm trying to import some elements from the vscode module:

//server.ts

import { workspace as Workspace } from 'vscode';

let sm_home: string = Workspace.getConfiguration("sourcepawnLanguageServer").get("sourcemod_home");
...

and in my package.json, I have:

  "dependencies": {
    "@types/glob": "^5.0.30",
    "@types/uuid": "^3.4.0",
    "@types/vscode": "^1.14.0",
    "glob": "^7.1.2",
    "uuid": "^3.1.0",
    "vscode-languageserver": "^7.0.0",
    "vscode-languageserver-textdocument": "^1.0.1",
    "vscode-test": "1.5.1",
    "vscode-uri": "^3.0.2"
  },

The whole project compiles fine, but when I start the extension, I get the following error:

Error: Cannot find module 'vscode'
Require stack:
- c:\Users\Charles\CloudStation\Documents\Perso\Dev\sourcepawn-vscode\server\out\server.js
    at Function._resolveFilename (internal/modules/cjs/loader.js:1019:15)
    at internal/modules/cjs/loader.js:895:27
    at Function._load (electron/js2c/asar_bundle.js:5:12738)
    at Module.require (internal/modules/cjs/loader.js:1079:19)
    at require (internal/modules/cjs/helpers.js:72:18)
    at Object.<anonymous> (c:\Users\Charles\CloudStation\Documents\Perso\Dev\sourcepawn-vscode\server\out\server.js:5:18)
    at Module._compile (internal/modules/cjs/loader.js:1199:30)
    at Object..js (internal/modules/cjs/loader.js:1220:10)
    at Module.load (internal/modules/cjs/loader.js:1039:32)
    at internal/modules/cjs/loader.js:932:14 {
  code: 'MODULE_NOT_FOUND',
  requireStack: [
    'c:\\Users\\Charles\\CloudStation\\Documents\\Perso\\Dev\\sourcepawn-vscode\\server\\out\\server.js'
  ]
}

And the error goes away if I remove the import and the line using the import in the server.ts file. This import works fine in index.ts` Could this be due to the fact that server.tsis called inside ofindex.ts` ?

import { ExtensionContext, workspace as Workspace, window, commands } from 'vscode';
import { LanguageClient, LanguageClientOptions, ServerOptions, TransportKind } from 'vscode-languageclient/node';
import * as glob from 'glob';
import * as path from 'path';

export const sm_home: string = 'Workspace.getConfiguration("sourcepawnLanguageServer").get("sourcemod_home")';

export function activate(context: ExtensionContext) {
    let serverModule = context.asAbsolutePath(
        path.join('server', 'out', 'server.js')
...

This doesn't seem to bother the C/C++ extension.

Thanks in advance for the help!