I have an array of vehicles that need to be grouped by make and model, only if the \'selected\' property is true. The resulting object should contain properties for make mod
I am not sure if this will solve Your problem, but in group_by You can add custom logic which allow You to create composite key.
Remember that SEPERATOR value should be defined accordingly to data source You work with, if "--" characters occur in model or type You should not used them as it will not allow You to reverse the process of grouping.
const SEPERATOR = "--";
_.chain(data).filter((item) => item.selected).groupBy((item)=>`${item.model}${SEPERATOR}${item.type}`).value();