title: Vue.js filrter not works with special character
body: <p>I have a filter witch looks inside a <code>items: {}</code> array, this array have 26 objects inside. The object <strong>24</strong> have an alias with special character <code>ñ</code>. The filter not works on this object and the next ones until the end of the items array.</p>
  
  <pre><code>items: {
      [...]
      23: {
        alias: "Correcto",
        id: 11
      },
      24: {
        alias: "Tamaño",
        id: 12
      }
      25: {
        alias: "silla",
        id: 13
      }
  };
  </code></pre>
  
  <p>This is the code of my filter as a <code>computed:</code> porperty</p>
  
  <pre><code>computed: {
        filteredItems() {
            if (this.items) {
                return this.items.filter((item) =&gt; {
                    if (!this.search) return '';
                    return item.alias.toLowerCase().match(this.search.toLowerCase().trim());
                });
            }
        }
    },
  </code></pre>
  
  <p>How can i make the filter works with any type of characters?</p>