what about 

```javascript
function move( src, prop, target ) {
  if ( src[prop] ) {
    target.push( src[prop] ); 
    delete src[prop];
  }
}

// Usage
move( options, 'routeTransform' , routeContext.options.routeTransforms );
```

I think that reads as clean as the inlined version. Only thing I is the asymmetry between src and target (one being obj the other array), perhaps a different name than `move` could mitigate that.