title: What is target in tsconfig.json for?
body: <p>What does <code>target</code> in <code>tsconfig.json</code> signify?</p>
  
  <pre><code>{
    "compilerOptions": 
    {
      "sourceMap": true,
      "target": "es5",
      "module": "commonjs",
      "jsx": "react",
      "moduleResolution": "classic",
      "lib": [ "es2015", "dom",  "es2017" ]
    }
  }
  </code></pre>