The Guardian's interactive team introduce a new JavaScript tool for manipulating webpages
Developers might point you towards a framework for templateing, such as AngularJS or EmberJS. These frameworks do a lot of the heavy lifting for you, particularly as far as model-view data binding is concerned.
But these frameworks also have a cost - they tend to be fairly large, and once you've finished the 'hello world' tutorials they have steep learning curves. Particularly for smaller projects, it's often a case of using a sledgehammer to crack a nut.
Ractive was initially created to tackle the data binding problem in a more elegant way.