title: Is getter construction can exist without associated property?
body: <p>For example, i have such code</p>
  
  <pre><code>get isChart(): Observable&lt;boolean&gt; {
    return this.isTemperatureChart.pipe(
      withLatestFrom(this.isHypertensionChart),
      map(([isTemperatureChart, isHypertensionChart]) =&gt; isTemperatureChart || 
           isHypertensionChart)
    );
  }
  </code></pre>
  
  <p>or for simplifying</p>
  
  <pre><code>get isChart(): boolean {
    return this.isTemperatureChart &amp;&amp; this.isSomeOtherPropertyTrue
  }
  </code></pre>
  
  <p>A long time, for me been obviously, that if I have complicated binary logic, and don't need for it any attributes from outside, I should use procedure. And just for clear code, all that times i try to use getters. But now i think, about a nature of this constructions, and can't find right answer. Is that ok, use getter just for GETTING, without associating it with some class property? Or is it not according to canons of OOP and getters/setters - only for encapsulation of class property?</p>