title: ngx-datatable in angular2 filter back results on backspace
body: <p>I am using ngx-datatable (<a href="http://swimlane.github.io/ngx-datatable/#filter" rel="nofollow noreferrer">http://swimlane.github.io/ngx-datatable/#filter</a>) in my angular project and trying to add a filter. The filter is added successfully on the column specified, however when I erase the filter characters with backspace, my original list data is not populated back.</p>
  
  <p>My HTML:</p>
  
  <pre><code>&lt;input
      type='text'
      style='padding:8px;margin:15px auto;width:30%;'
      placeholder='Type to filter the task name column...'
      (keyup)='updateFilter($event)'
    /&gt;
  &lt;div&gt;
      &lt;ngx-datatable  class="material"
      [rows]="tasks"
      [columns]="columns"&gt;
  &lt;/ngx-datatable&gt;
  </code></pre>
  
  <p>and in my component I have:</p>
  
  <pre><code>rows = [];
  columns = [
  { name: 'Id' },
  { name: 'What task', prop: 'what_task' },
  { name: 'Budget', prop:'tentative_budget' }
  ];
  
  temp = [];
  ngOnInit() {
  
      this.taskListService.getTasks().subscribe(
          tasks =&gt; {
              console.log(tasks);
              this.tasks=tasks;
              this.tableData=this.tasks;
              this.tableModel.addAll(this.tableData);
  
          }
          )
  }
  
  updateFilter(event) {
      const val = event.target.value.toLowerCase();
  
      // filter our data
      const temp = this.tasks.filter(function(d) {
          console.log(d.what_task.toLowerCase().indexOf(val) !== -1 || !val)
          return d.what_task.toLowerCase().indexOf(val) !== -1 || !val;
      });
  
      // update the rows
      this.tasks = temp;
  
  }
  </code></pre>
  
  <p>What am I missing?</p>