title: Use findIndex, but start looking in a specific position
body: <p>I have the following extract of code:</p>
  
  <pre><code>private getNextFakeLinePosition(startPosition: number): number{
          return this.models.findIndex(m =&gt; m.fakeObject);
  }
  </code></pre>
  
  <p>This function returns me the index of the first element which has the property <code>fakeObject</code> with the true value.</p>
  
  <p>What I want is something like this, but instead of looking for the all items of the array, I want to start in a specific position (<code>startPosition</code>).</p>
  
  <p>Note: This is typescript but the solution could be in javascript vanilla.</p>
  
  <p>Thank you.</p>