lodash chaining groupBy - object

Question

I'm trying to figure out how to convert an array of vehicle objects, that are only unique by trim/year, to an array nested object properties. Originally I was looping through all of the properties to organize the vehicles into a hierarchical structure of arrays i.e., make[model[trim[year[]]]], but I think it would be faster to look up the vehicles by object properties i.e., make.model.trim.year. I'm a lodash noob so I'm not sure how to go about this.
The data returned is structured like this:
[
{
id:1
makeCode:"Make1"
modelCode:"Modela"
selected:true
trimCode:"D"
yearCode:"2014"
},
{
id:2
makeCode:"Make1"
modelCode:"Modela"
selected:true
trimCode:"D"
yearCode:"2015"
},
{
id:3
makeCode:"Make1"
modelCode:"Modela"
selected:true
trimCode:"D"
yearCode:"2016"
},
{
id:4
makeCode:"Make1"
modelCode:"Modela"
selected:true
trimCode:"LX"
yearCode:"2014"
},
{
id:5
makeCode:"Make1"
modelCode:"Modela"
selected:true
trimCode:"LX"
yearCode:"2015"
},
{
id:6
makeCode:"Make1"
modelCode:"Modela"
selected:true
trimCode:"LX"
yearCode:"2016"
},
{
id:7
makeCode:"Make2"
modelCode:"Modelb"
selected:true
trimCode:"D"
yearCode:"2014"
},
{
id:8
makeCode:"Make2"
modelCode:"Modelb"
selected:true
trimCode:"D"
yearCode:"2015"
},
{
id:9
makeCode:"Make2"
modelCode:"Modelb"
selected:true
trimCode:"D"
yearCode:"2016"
}
]
This is working correctly to get the objects ordered by makeCode:
vm.makeGroups = _.groupBy(vm.selectedVehcileTypes, function(v) { return v.makeCode});
but I would like to do this on every level, so I have something like:
vm.makeGroups = _.groupBy(vm.selectedVehcileTypes, function(v) { return v.makeCode});
vm.modelGroups = _.groupBy(vm.makeGroups, function(v) { return v.modelCode});
vm.trimGroups = _.groupBy(vm.modelGroups, function(v) { return v.trimCode});
Basically I want to chain the grouping so that the end result looks like this:
{
Make1: {
modela: {
D: {
'2012': false,
'2013': false
'2014': true // selected
}
}
}
}
}
Any help is appreciated, thanks.

Answer 1

The solution below uses a combination of _.reduce() and _.setWith() as the primary functions to obtain the final result.
// array: Collection of objects
// keysPath: The path of the of the
// property to set check _.setWith docs
// keyValue: The value of each property
function getResult(array, keysPath, keyValue) {
// This is used to get the values from the keysPath
var getValue = _.curry(_.get, 2);
return _.reduce(array, function(result, item) {
// get path
var path = _.map(keysPath, getValue(item));
// set property values, note that using `Object` as a customizer
// makes sure that yearCode is not treated as an index of an array
// but an index of an object
return _.setWith(result, path, item[keyValue], Object);
}, {});
}
var result = getResult(
data,
['makeCode', 'modelCode', 'trimCode', 'yearCode'],
'selected'
);
var data = [
{
id:1,
makeCode:"Make1",
modelCode:"Modela",
selected:true,
trimCode:"D",
yearCode:"2014"
},
{
id:2,
makeCode:"Make1",
modelCode:"Modela",
selected:true,
trimCode:"D",
yearCode:"2015"
},
{
id:3,
makeCode:"Make1",
modelCode:"Modela",
selected:true,
trimCode:"D",
yearCode:"2016"
},
{
id:4,
makeCode:"Make1",
modelCode:"Modela",
selected:true,
trimCode:"LX",
yearCode:"2014"
},
{
id:5,
makeCode:"Make1",
modelCode:"Modela",
selected:true,
trimCode:"LX",
yearCode:"2015"
},
{
id:6,
makeCode:"Make1",
modelCode:"Modela",
selected:true,
trimCode:"LX",
yearCode:"2016"
},
{
id:7,
makeCode:"Make2",
modelCode:"Modelb",
selected:true,
trimCode:"D",
yearCode:"2014"
},
{
id:8,
makeCode:"Make2",
modelCode:"Modelb",
selected:true,
trimCode:"D",
yearCode:"2015"
},
{
id:9,
makeCode:"Make2",
modelCode:"Modelb",
selected:true,
trimCode:"D",
yearCode:"2016"
}
];
function getResult(array, keysPath, keyValue) {
var getValue = _.curry(_.get, 2);
return _.reduce(array, function(result, item) {
var path = _.map(keysPath, getValue(item));
return _.setWith(result, path, item[keyValue], Object);
}, {});
}
var result = getResult(
data,
['makeCode', 'modelCode', 'trimCode', 'yearCode'],
'selected'
);
document.write('<pre>' + JSON.stringify(result, 0, 4) + '</pre>');
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