Adamduehansen•3w ago

Cannot assign number to "number | undefined" when using package.json

Hi. I'm having odd behavior when using a newly created Vite vanilla TypeScript template using deno init --npm vite@latest. Right after initialization I'm installing the game library https://www.npmjs.com/package/excalibur. A game object in the engine is written like this:

import * as ex from "excalibur";

class GameObject extends ex.Actor {
  constructor(args: ex.ActorArgs) {
    super({
      ...args,    
      width: 16,
      height: 16
    });
  }
}

import * as ex from "excalibur";

class GameObject extends ex.Actor {
  constructor(args: ex.ActorArgs) {
    super({
      ...args,    
      width: 16,
      height: 16
    });
  }
}

but the lsp shows error on the width and height properties. It says

Type 'number' is not assignable to type 'undefined'.

though they are both a type of number | undefined. If I replace the package.json file with a deno.json file and reinstalls the node_modules it all works. I have tested on two machines. Is it a bug or am I missing something? Here is how I reproduce: 1. Run deno init --npm vite@latest test-exc, select Vanilla, select TypeScript 2. Run deno install inside the project. 3. Add the Excalibur dependency with deno add npm:excalibur 4. Replace the contents of main.ts with

import * as ex from "excalibur";

class GameObject extends ex.Actor {
  constructor(args: ex.ActorArgs) {
    super({
      ...args,
      width: 16,
      height: 16,
    });
  }
}

import * as ex from "excalibur";

class GameObject extends ex.Actor {
  constructor(args: ex.ActorArgs) {
    super({
      ...args,
      width: 16,
      height: 16,
    });
  }
}

5. At this point I have errors on width and height. 6. Delete the package.json and create a deno.json file with this content:

{
  "tasks": {
    "dev": "deno run -A --node-modules-dir npm:vite",
    "build": "deno run -A --node-modules-dir npm:vite build",
    "serve": "deno run --allow-net --allow-read https://deno.land/std@0.157.0/http/file_server.ts dist/"
  },
  "imports": {
    "excalibur": "npm:excalibur@^0.29.3",
    "vite": "npm:vite@^5.4.8"
  },
  "compilerOptions": {
    "lib": [
      "deno.window",
      "DOM"
    ]
  },
  "lint": {
    "exclude": [
      "dist"
    ]
  }
}

{
  "tasks": {
    "dev": "deno run -A --node-modules-dir npm:vite",
    "build": "deno run -A --node-modules-dir npm:vite build",
    "serve": "deno run --allow-net --allow-read https://deno.land/std@0.157.0/http/file_server.ts dist/"
  },
  "imports": {
    "excalibur": "npm:excalibur@^0.29.3",
    "vite": "npm:vite@^5.4.8"
  },
  "compilerOptions": {
    "lib": [
      "deno.window",
      "DOM"
    ]
  },
  "lint": {
    "exclude": [
      "dist"
    ]
  }
}

6. Fix the import to npm:excalibur, remove the node_modules folder, and reinstall with deno install. 7: Errors are gone.

2 Replies

CodyC•3w ago

Could they be resolving different versions of the npm:excalibur library? (Check its version in package-lock.json and deno.lock files)

AdamduehansenOP•3w ago

Oh yeah, I didn't check for different versions. I'll give it another shot. I think they resolved to same version, but now I noticed a warning in the terminal that I might not have payed attention to before:

Warning The following packages contained npm lifecycle scripts (preinstall/install/postinstall) that were not executed: ┠─ npm:core-js@3.36.1 ┃ ┠─ This may cause the packages to not work correctly. ┖─ To run lifecycle scripts, use the --allow-scripts flag with deno install: deno install --allow-scripts=npm:core-js@3.36.1

I ran the command and now the errors are gone :deno_it_works:

Cannot assign number to "number | undefined" when using package.json

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