title: Knockout.js attr error when combining string literal and object value
body: <p>Working a new project using Knockout, the base documentation didn't seem to explain a case as below. Using the below attr calling; An incorrect href is produced:
  <strong>"api/degrees/function c(){if(0"</strong></p>
  
  <pre><code>&lt;a data-bind="attr: { href: '/api/degrees/' + fieldId }"&gt;
  </code></pre>
  
  <p>Although the following produces the fieldId value correctly</p>
  
  <pre><code>&lt;a data-bind="attr: { href: fieldId }"&gt;
  </code></pre>
  
  <p>Is the only way to successfully combine the base url string and JS object value to use a Knockout computed value?</p>
  
  <p>Thanks in advance for the help.</p>