title: What type of JavaScript term/definition fits this?
body: <p>I was reading the <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Classes" rel="nofollow noreferrer">MDN documentation on JavaScript classes</a> and came across an example of assigning values that I did not understand. The lines in question were not explained because the page was simply explaining something else (static methods). I am fascinated though with how it worked and what this would be officially called so that I can research it further.</p>
  
  <pre><code> class Point {
    constructor(x, y) {
      this.x = x;
      this.y = y;
    }
    static distance(a, b) {
      const dx = a.x - b.x;
      const dy = a.y - b.y;
      return Math.hypot(dx, dy);
    }
  }
  </code></pre>
  
  <p>What I don't understand specifically is the <code>a.x</code>, <code>b.x</code>, <code>a.y</code> and <code>b.y</code>. I wouldn't consider this dot notation because dot notation is defined as <em>"In JavaScript, one can access properties using the dot notation..."</em>. So if this is not dot notation, then what term would apply to the value of <code>x</code> and <code>y</code> being assigned to <code>a</code> and <code>b</code>? </p>
  
  <p>Wouldn't the letters <code>a</code> and <code>b</code> in line -</p>
  
  <pre><code>static distance(a, b)
  </code></pre>
  
  <p>technically be called "parameters" which is clearly defined as something other than a property. And since they are "parameters", then the word "property" would not apply, therefore the official definition of dot notation does not apply.</p>
  
  <p>Definition of parameter: <em>Parameters are variables listed as a part of the function definition</em></p>
  
  <p>Definition of property:  <em>has a value, which may or may not be writable</em></p>
  
  <p>Definition of dot notation: <em>In JavaScript, one can access properties using the dot notation...</em></p>