How can I populate the abn-tree from a text file?

[mamacasc]

I am able to populate the abn-tree by hard-coding data in my angularJS controller, e.g.
var vm = this;
vm.tran_data = [{
label: 'Transactions',
children: ['Top node', 'Next node'}]
I then reference tran_data in the html:

But I may have hundreds of nodes and want to put the data in a file that can be referenced instead of hard-coding the data in the controller. Can I do that and if so, what would the format of the data in the file be?
Thanks.