Please checkout this JS Bin
http://jsbin.com/iqikuf/3/edit
When the below is run in the console, the result shown makes sense to me.
statement: vd.tools.push(dataItem);
resuelt: 2
But why do we get the below result when run in the console?
statement: vd.tools.length
result: 0
As DCoder pointed out
parentheses needed
vd.tools().length