title: Declare an array in TypeScript
body: <p>I'm having trouble either declaring or using a boolean array in Typescript, not sure which is wrong. I get an <code>undefined</code> error. Am I supposed to use JavaScript syntax or declare a new Array object? </p>
  
  <p>Which one of these is the correct way to create the array?</p>
  
  <pre><code>private columns = boolean[];
  private columns = [];
  private columns = new Array&lt;boolean&gt;();
  </code></pre>
  
  <p>How would I initialize all the values to be false?</p>
  
  <p>How would I access the values, can I access them like, <code>columns[i] = true;</code>..?</p>