typescript-is introduces "typescript" dependency into production environment

[acomagu]

typescript-is depends on typescript package indirectly, so typescript compiler is installed whenever we use typescript-is, even if in production environment.

typescript package has a size of 64MB. This is too big to ignore(e.g. The limit of AWS Lambda asset is 250MB)

Reproduction

package.json:

{
  "dependencies": {
    "express": "^4.17.1",
    "typescript-is": "^0.19.0"
  },
  "devDependencies": {
    "@types/express": "^4.17.13",
    "ttypescript": "^1.5.12",
    "typescript": "^4.5.2"
  }
}

Then, NODE_ENV=production npm i installs typescript.

npm why:

$ npm why typescript
[email protected]
node_modules/typescript
  dev typescript@"^4.5.2" from the root project
  peer typescript@">=2.8.0 || >= 3.2.0-dev || >= 3.3.0-dev || >= 3.4.0-dev || >= 3.5.0-dev || >= 3.6.0-dev || >= 3.6.0-beta || >= 3.7.0-dev || >= 3.7.0-beta"
from [email protected]
  node_modules/tsutils
    tsutils@"^3.17.1" from [email protected]
    node_modules/typescript-is
      typescript-is@"^0.19.0" from the root project
  peer typescript@"^4.1.5" from [email protected]
  node_modules/typescript-is
    typescript-is@"^0.19.0" from the root project

p.s. Thank you for awesome project! I'm using this to validate the API Request/Response, DB entity, and so on in production environment. I really love this.