http://stackoverflow.com/questions/42303187/pass-observable-to-component-through-component

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout/3.4.1/knockout-min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/knockout.mapping/2.4.1/knockout.mapping.min.js"></script>
<div>
  <view-model></view-model>
</div>

JavaScript

ko.components.register('view-model', {
  viewModel: function(){
  	this.myParameter = ko.observable("Topst");
  },
  template: 
    '<div style="border: 1px solid blue; width:600px; margin:auto; padding: 32px; text-align:center;">\
    <h3>\
      Main Component\
    </h3>\
    <view-model2 params="{ data: $data.myParameter}"></view-model2>\
  </div>'
});

ko.components.register('view-model2', {
  viewModel: function(params){
    var self = this;

    self.myObservable = params.data;
    return this;
  },
  template: 
  '<div style="border: 1px solid blue; margin:auto; padding: 32px; text-align:center;">\
    <h3>\
      Child Component\
    </h3>\
    <span data-bind="text: myObservable"></span>\
	</div>'
});
    
ko.applyBindings();