title: Type 'string[]' is not assignable to type 'string'. when using Date object
body: <p>I have component that gets data from a class/model (projInfo), including a date object. 
  I need to use the different parts of the date (day/month/year) formatted such that i need to break them up and put them in an array. </p>
  
  <p>I can't seem to parse the Date object into a string[] type. Here's what I have:</p>
  
  <pre><code>  public _startDate = this.projInfo.startdato; //.toString();
  
    @Input()
    set startDate(startDate: string) {
      // remove commas then split into array
      const d: string = this.startDateFormat.replace(',', '');
      this._startDate = d.split(' ');
    }
  </code></pre>
  
  <p>"this._startDate" on last line provides and error  <code>Type 'string[]' is not assignable to type 'string'</code>.<br>
  How do I solve this? It's hard to search for answers because I think the error is too broad. </p>