Linq.js Group By the time Group By, how can this be achieved?
I want something that will lead to this
[{
firstName: "Sam",
lastName: "Smith"
}, {
firstName: "Sam",
lastName: "Doe"
}, {
firstName: "Sam",
lastName: "Doe"
}, {
firstName: "Sam",
lastName: "Joe"
}]
Be something similar, except for the number of columns the group is not grouped into, and the order of the columns.
[{
"Sam": [{
"Smith": [{
firstName: "Sam",
lastName: "Smith"
}]
}, {
"Doe": [{
firstName: "Sam",
lastName: "Doe"
}, {
firstName: "Sam",
lastName: "Doe"
}]
}, {
"Joe": [{
firstName: "Sam",
lastName: "Joe"
}]
}]
}]
I want to be able to create something like the following photo demonstrates
I have tried several times but I cannot figure it out, please help me :).
source to share
I suggest a different output structure. Your structure looks convenient at first glance, but it will be unnecessarily difficult to process when further processed.
I would suggest this general structure:
[
{
key: "group 1",
items: [{
key: "group 1.1",
items: [ {}, {}, {} ]
}, {
key: "group 1.2",
items: [ {}, {} ]
}]
}, {
key: "group 2",
items: [{
key: "group 2.1",
items: [ {}, {}, [}, {} ]
}, {
key: "group 2.2",
items: [ {} ]
}]
}
]
You can create a structure like this relatively easily:
var grouped = Enumerable.From(input).GroupBy("$.firstName", "", function(key, e) {
return {
key: key,
items: e.GroupBy("$.lastName", "", function (key, e) {
return {
key: key,
items: e.ToArray()
};
}).ToArray()
};
}).ToArray();
when applied to this input
:
var input = [{
firstName: "Sam",
lastName: "Smith"
}, {
firstName: "Sam",
lastName: "Doe"
}, {
firstName: "Sam",
lastName: "Doe"
}, {
firstName: "Sam",
lastName: "Joe"
},{
firstName: "John",
lastName: "Joe"
}];
leads to
[
{
"key": "Sam",
"items": [
{
"key": "Smith",
"items": [
{
"firstName": "Sam",
"lastName": "Smith"
}
]
},
{
"key": "Doe",
"items": [
{
"firstName": "Sam",
"lastName": "Doe"
},
{
"firstName": "Sam",
"lastName": "Doe"
}
]
},
{
"key": "Joe",
"items": [
{
"firstName": "Sam",
"lastName": "Joe"
}
]
}
]
},
{
"key": "John",
"items": [
{
"key": "Joe",
"items": [
{
"firstName": "John",
"lastName": "Joe"
}
]
}
]
}
]
Edit. To allow dynamically custom grouping and ordering, a more advanced approach needs to be taken:
// Enumerable, definition => Enumerable
function applyOrder(items, definition) {
var i, prop, prefix, suffix, orderFunc;
if (!items) return;
if (!definition) return items;
for (i = 0; i < definition.length; i++) {
// definition[i] is either "propertyName" or "propertyName DESC"
prop = (definition[i] + " ").split(" ");
prefix = i === 0 ? "OrderBy" : "ThenBy";
suffix = prop[1].toUpperCase() === "DESC" ? "Descending" : "";
orderFunc = prefix + suffix;
items = items[orderFunc]("$." + prop[0]);
}
return items;
}
// Enumerable, definition => Enumerable
function applyGroup(items, definition) {
if (!items) return;
if (!definition) return items;
items = applyOrder(items, definition.order);
if (!definition.group) return items;
return items.GroupBy("$." + definition.group, "", function (key, e) {
return {
group: definition.group,
key: key,
items: applyGroup(e, definition.then).ToArray()
};
});
}
// Array, definition => Array
function applyStructure(items, definition) {
if (!items) return;
if (!definition) return items;
return applyGroup(Enumerable.From(items), definition).ToArray();
}
used like this:
var result = applyStructure(companies, {
group: "country",
order: ["country"],
then: {
group: "city",
order: ["city"],
then: {
order: ["companyName DESC"]
}
}
});
source to share