title: Regex: Specify "space or start of string" and "space or end of string"
body: <p>Imagine you are trying to pattern match "stackoverflow".</p>
  
  <p>You want the following:</p>
  
  <pre><code> this is stackoverflow and it rocks [MATCH]
  
   stackoverflow is the best [MATCH]
  
   i love stackoverflow [MATCH]
  
   typostackoverflow rules [NO MATCH]
  
   i love stackoverflowtypo [NO MATCH]
  </code></pre>
  
  <p>I know how to parse out stackoverflow if it has spaces on both sites using:</p>
  
  <pre><code>/\s(stackoverflow)\s/
  </code></pre>
  
  <p>Same with if its at the start or end of a string:</p>
  
  <pre><code>/^(stackoverflow)\s/
  
  /\s(stackoverflow)$/
  </code></pre>
  
  <p>But how do you specify "space or end of string" and "space or start of string" using a regular expression?</p>