Prerequisites

Minimum supported version 4.6.

For even more type-safety and accurate inference, use version 5.4 or later.

For improved compilation performance, use version 5.9 or later.

You must enable strict mode in your tsconfig.json file's compilerOptions:

{
  // ...
  "compilerOptions": {
    // ...
    "strict": true
    // ...
  }
  // ...
}