javascript - Appcelerator / Titanium Alloy - how to manipulate a string before it gets added to the view -

i have titanium alloy view, outputs tableview image thumbnail each one. achieved passing url image attribute of imageview element. alloy view populated alloy collection, handles looping of data me:

<tableview id="brandslist" datacollection="brands">     <tableviewrow brandid="{brand_id}">         <view class="vgroup">             <imageview height="45" width="80" id="image" image="{image}" />             <label id="name" text="{name}" />            </view>                  </tableviewrow> </tableview> 

however, i'd change url string bit before gets view above. specially need add values in middle of url change image quality , size. how can catch string string value , make changes?

from looks of code appears doing data-binding. can transform data before presented in view

http://docs.appcelerator.com/titanium/latest/#!/guide/alloy_data_binding

<tableview id="brandslist" datacollection="brands"  datatransform="transformfunction">     <tableviewrow brandid="{brand_id}">         <view class="vgroup">             <imageview height="45" width="80" id="image" image="{image}" />             <label id="name" text="{name}" />            </view>                  </tableviewrow> </tableview> 

then in code

function transformfunction(model) {     // need convert model json object     var transform = model.tojson();     transform.image = /* someting image url string */;     return transform; }