title: Assignment to property of function parameter 'a' Eslint
body: <p>I am trying to sort array of object with custom function. <br/>
  So, I define my function </p>
  
  <pre><code>   sortingAlgo = (a, b) =&gt; {
          // we need to use custom sorting algorithm to meet our requirements.
          a.pos = a.pos.toUpperCase();
          b.pos = b.pos.toUpperCase();
          if(a.pos.slice(0, 1) === b.pos.slice(0, 1)) {
            if (parseInt(a.pos.slice(1)) &lt; parseInt(b.pos.slice(1))){
              return -1;
            }
            if (parseInt(a.pos.slice(1)) &gt; parseInt(b.pos.slice(1))){
              return 1;
            }
            return 0;
          } else {
            if (parseInt(a.pos.slice(0, 1)) &lt; parseInt(b.pos.slice(0, 1))){
              return -1;
            }
            if (parseInt(a.pos.slice(0, 1)) &gt; parseInt(b.pos.slice(0, 1))){
              return 1;
            }
            return 0;
  
          }
        }
  </code></pre>
  
  <p>And i call it like this.</p>
  
  <pre><code>const sortedProducts = data.data.sort(this.sortingAlgo);
  </code></pre>
  
  <p>Now i Got Eslint error saying. </p>
  
  <p>**</p>
  
  <ul>
  <li>169:5   error    Assignment to property of function parameter 'a' 
  no-param-reassign</li>
  <li>170:5   error    Assignment to property of function parameter 'b' 
  no-param-reassign</li>
  </ul>
  
  <p>**</p>
  
  <p>I searched and found that this rule is set byt airBnB. So i dont think its right to disable this rule.
  <br/>So can somebody tell me how to resolve it or if disabling this rule is okay.</p>