All the functional operators of DataModel works in similar way. They accepts arguments which are specific for a operator and returns a function. This function is called PreparatorFunction. This function expects a DataModel instance, performs the oprerator(s) on the instance and return a resultant DataModel instance.
const project = DataModel.operators.project; const fn = project(['horsepower', 'miles_per_gallon']); // fn <- preparator function fn(dm);
Instance of DataModel on which operator has to be applied