title: TypeScript error TS5023: Unknown compiler option 'strict'
body: <p>When using the option "strict" in <code>tsconfig.json</code> file, I get the error: </p>
  
  <pre><code>error TS5023: Unknown compiler option 'strict'
  </code></pre>
  
  <p>But this compiler option is clearly allowed in the official documentation:</p>
  
  <p>Reference: <a href="https://www.typescriptlang.org/docs/handbook/compiler-options.html" rel="noreferrer">https://www.typescriptlang.org/docs/handbook/compiler-options.html</a></p>
  
  <p>And also my Visual Studio Code editor. </p>
  
  <p>Does anyone know what I did wrong? Here is my tsconfig.json file:</p>
  
  <pre><code>{
    "compilerOptions": {
      "strict": true,
      "sourceMap":  true
    }
  }
  </code></pre>