title: Regex to check if JSON contains an array
body: <p>I need to be able to quickly discern whether or not a JSON data structure contains an array in it. For example the regex should return <code>true</code> for</p>
  
  <pre><code>{
    "array": [
      1,
      2,
      3
    ],
    "boolean": true,
    "null": null,
    "number": 123,
    "object": {
      "a": "b",
      "c": "d",
      "e": "f"
    },
    "string": "Hello World"
  }
  </code></pre>
  
  <p>and <code>false</code> for</p>
  
  <pre><code>{
    "boolean": true,
    "null": null,
    "number": 123,
    "object": {
      "a": "b",
      "c": "d",
      "e": "f"
    },
    "string": "[Hello World]"
  }
  </code></pre>
  
  <p>Any ideas? </p>
  
  <p>I Would MUCH prefer if this check could be done via regex instead of traversing json, unless anyone can show me a better way.</p>