title: Using .includes method in a function
body: <p>I have a an object <code>jsonRes[0]</code> containing values which need to be removed based on a condition.  The following works to remove <code>null</code>,  missing values and those equal to zero in the stringified object: </p>
  
  <pre><code>function replacer(key, value) {
            // Filtering out properties
            if (value === null || value === 0 || value === "") {
              return undefined;
            }
            return value;
          } 
  
  JSON.stringify(jsonRes[0], replacer, "\t")
  </code></pre>
  
  <p>However, when I add a condition using the the <code>includes</code> method, I receive an error:</p>
  
  <pre><code>function replacer(key, value) {
            // Filtering out properties
            if (value === null || value === 0 || value === "" || value.includes("$")) {
              return undefined;
            }
            return value;
          } 
  
  
  Uncaught TypeError: value.includes is not a function
  </code></pre>
  
  <p>Why is this the case and is there a workaround? </p>