Using lodash.groupBy() to normalise objects
0
I have a denormalized array of three different objects - country, school, student
const input=
[
{
countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 142,
studentName: "Mary"
},
{
countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 145,
studentName: "John"
},
{
countryID: 14,
country: "UK",
schoolID: 222,
schoolZone: "Leeds",
studentID: 223,
studentName: "Peter"
}
];
I would like to normalise them like this
const result=
[
{
countryID: 12,
country: "US",
schools: [
{
schoolID: 122,
schoolZone: "Highlands",
students: [
{
studentID: 142,
studentName: "Mary"
},
{
studentID: 145,
studentName: "John"
}
]
}
]
},
{
countryID: 14,
country: "UK",
schools: [
{
schoolID: 222,
schoolZone: "Leeds",
students: [
{
studentID: 223,
studentName: "Peter"
}
]
}
]
}
];
I understand lodash and ramda can be used to achieve nested normalisation
But I am new to both libraries.
Could you please help me with an implementation ? Also wondering if currying would be a consideration given there is nesting of schools and students
javascript lodash ramda.js
asked Nov 24 '18 at 11:39
Theepan ThevathasasnTheepan Thevathasasn
5819
add a comment |
0
I have a denormalized array of three different objects - country, school, student
const input=
[
{
countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 142,
studentName: "Mary"
},
{
countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 145,
studentName: "John"
},
{
countryID: 14,
country: "UK",
schoolID: 222,
schoolZone: "Leeds",
studentID: 223,
studentName: "Peter"
}
];
I would like to normalise them like this
const result=
[
{
countryID: 12,
country: "US",
schools: [
{
schoolID: 122,
schoolZone: "Highlands",
students: [
{
studentID: 142,
studentName: "Mary"
},
{
studentID: 145,
studentName: "John"
}
]
}
]
},
{
countryID: 14,
country: "UK",
schools: [
{
schoolID: 222,
schoolZone: "Leeds",
students: [
{
studentID: 223,
studentName: "Peter"
}
]
}
]
}
];
I understand lodash and ramda can be used to achieve nested normalisation
But I am new to both libraries.
Could you please help me with an implementation ? Also wondering if currying would be a consideration given there is nesting of schools and students
javascript lodash ramda.js
asked Nov 24 '18 at 11:39
Theepan ThevathasasnTheepan Thevathasasn
5819
add a comment |
0
0
0
I have a denormalized array of three different objects - country, school, student
const input=
[
{
countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 142,
studentName: "Mary"
},
{
countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 145,
studentName: "John"
},
{
countryID: 14,
country: "UK",
schoolID: 222,
schoolZone: "Leeds",
studentID: 223,
studentName: "Peter"
}
];
I would like to normalise them like this
const result=
[
{
countryID: 12,
country: "US",
schools: [
{
schoolID: 122,
schoolZone: "Highlands",
students: [
{
studentID: 142,
studentName: "Mary"
},
{
studentID: 145,
studentName: "John"
}
]
}
]
},
{
countryID: 14,
country: "UK",
schools: [
{
schoolID: 222,
schoolZone: "Leeds",
students: [
{
studentID: 223,
studentName: "Peter"
}
]
}
]
}
];
I understand lodash and ramda can be used to achieve nested normalisation
But I am new to both libraries.
Could you please help me with an implementation ? Also wondering if currying would be a consideration given there is nesting of schools and students
javascript lodash ramda.js
asked Nov 24 '18 at 11:39
Theepan ThevathasasnTheepan Thevathasasn
5819
I have a denormalized array of three different objects - country, school, student
const input=
[
{
countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 142,
studentName: "Mary"
},
{
countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 145,
studentName: "John"
},
{
countryID: 14,
country: "UK",
schoolID: 222,
schoolZone: "Leeds",
studentID: 223,
studentName: "Peter"
}
];
I would like to normalise them like this
const result=
[
{
countryID: 12,
country: "US",
schools: [
{
schoolID: 122,
schoolZone: "Highlands",
students: [
{
studentID: 142,
studentName: "Mary"
},
{
studentID: 145,
studentName: "John"
}
]
}
]
},
{
countryID: 14,
country: "UK",
schools: [
{
schoolID: 222,
schoolZone: "Leeds",
students: [
{
studentID: 223,
studentName: "Peter"
}
]
}
]
}
];
I understand lodash and ramda can be used to achieve nested normalisation
But I am new to both libraries.
Could you please help me with an implementation ? Also wondering if currying would be a consideration given there is nesting of schools and students
javascript lodash ramda.js
javascript lodash ramda.js
asked Nov 24 '18 at 11:39
Theepan ThevathasasnTheepan Thevathasasn
5819
asked Nov 24 '18 at 11:39
Theepan ThevathasasnTheepan Thevathasasn
5819
asked Nov 24 '18 at 11:39
Theepan ThevathasasnTheepan Thevathasasn
5819
asked Nov 24 '18 at 11:39
Theepan ThevathasasnTheepan Thevathasasn
5819
asked Nov 24 '18 at 11:39
Theepan ThevathasasnTheepan Thevathasasn
5819
5819
add a comment |
add a comment |
3 Answers
3
active
oldest
votes
1
A way without using lodash or ramda could be this. Hope this helps.
const input= [{
countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 142,
studentName: "Mary"
}, {
countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 145,
studentName: "John"
}, {
countryID: 14,
country: "UK",
schoolID: 222,
schoolZone: "Leeds",
studentID: 223,
studentName: "Peter"
}];
const normalize = (data) =>
data.reduce((acc, { studentID, studentName, schoolID, schoolZone, countryID, country }) => {
const studentToAdd = { studentID, studentName };
const schoolToAdd = { schoolID, schoolZone, students: [studentToAdd] };
const countryToAdd = { countryID, country, schools: [schoolToAdd] };
const existingCountry = acc.find(item => item.countryID === countryID);
if (existingCountry) {
const existingSchool = existingCountry.schools.find(item => item.schoolID === schoolID);
if (existingSchool) {
const existingStudent = existingSchool.students.find(item => item.studentID === studentID);
if (!existingStudent) existingSchool.students.push(studentToAdd);
}
else existingCountry.schools.push(schoolToAdd);
}
else acc.push(countryToAdd);
return acc;
}, );
console.log(normalize(input));answered Nov 24 '18 at 15:09
Alex GAlex G
1,221139
add a comment |
1
With lodash you can solve this in the following concise way:
const data = [{ countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 142, studentName: "Mary" }, { countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 145, studentName: "John" }, { countryID: 14, country: "UK", schoolID: 222, schoolZone: "Leeds", studentID: 223, studentName: "Peter" } ];
const grp = (arr, key, field, group, o=0) => _(arr)
.groupBy(key)
.mapValues(x => ({
[key]: _.head(x)[key],
[field]: _.head(x)[field],
[group]: o
? _.map(x, s => _.pick(s, ['studentID', 'studentName']))
: grp(x, 'schoolID', 'schoolZone', 'students', 1)
}))
.values()
.value()
console.log(grp(data, 'countryID', 'country', 'schools'))<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.10/lodash.min.js"></script>The idea is to use recursive approach where you call the same grouping function 2 times. Inside of which we would _.groupBy and just do _.mapValues
Now the exact same idea with compact ES6 code would look like:
const data = [{ countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 142, studentName: "Mary" }, { countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 145, studentName: "John" }, { countryID: 14, country: "UK", schoolID: 222, schoolZone: "Leeds", studentID: 223, studentName: "Peter" } ];
const groupBy = (arr, k) => arr.reduce((r,c) => (r[c[k]] = [...r[c[k]] || , c], r), {})
const pick = (obj, fields) => fields.reduce((r,f) => (r[f] = obj[f], r), {})
const grp = (arr, k, f, b, o=0) =>
Object.values(Object.values(groupBy(arr, k)).map(x => ({
[k]: x[0][k],
[f]: x[0][f],
[b]: o
? x.map(s => pick(s, ['studentID', 'studentName']))
: grp(x, 'schoolID', 'schoolZone', 'students', 1)
})))
console.log(grp(data, 'countryID', 'country', 'schools'))answered Nov 24 '18 at 23:25
AkrionAkrion
9,45511224
add a comment |
0
First reshape each object to look like the final data structure:
reshape({
countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 142,
studentName: "Mary" });
//=> {
//=> country: "US",
//=> countryID: 12,
//=> schools: [
//=> {
//=> schoolID: 122,
//=> schoolZone: "Highlands",
//=> students: [
//=> {
//=> studentID: 142,
//=> studentName: "Mary"
//=> }
//=> ]
//=> }
//=> ]
//=> }
Then it is simply a matter of grouping by countries then by schools and using a map & reduce function to merge objects.
const {pick, map, groupBy, values, lensProp, over, reduce, mergeWithKey, pipe, prop, applySpec, converge, set, of} = R;
const input = [
{ countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 142,
studentName: "Mary" },
{ countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 145,
studentName: "John" },
{ countryID: 14,
country: "UK",
schoolID: 222,
schoolZone: "Leeds",
studentID: 223,
studentName: "Peter" }];
const reshape = applySpec({
countryID: prop('countryID'),
country: prop('country'),
schools: converge(
pipe(set(lensProp('students')), of), [
pipe(pick(['studentID', 'studentName']), of),
pick(['schoolID', 'schoolZone'])])
});
const mergeArrays = key => mergeWithKey((k, a, b) => k === key ? [a[0], b[0]] : a);
const groupStudents = pipe(
groupBy(prop('schoolID')),
values,
map(reduce(mergeArrays('students'), {})));
const process = pipe(
map(reshape),
groupBy(prop('countryID')),
map(reduce(mergeArrays('schools'), {})),
map(over(lensProp('schools'), groupStudents)),
values);
console.log(process(input));<script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.25.0/ramda.min.js"></script>answered Nov 24 '18 at 13:47
customcommandercustomcommander
1,73111019
add a comment |
Your Answer
StackExchange.ifUsing("editor", function () {
StackExchange.using("externalEditor", function () {
StackExchange.using("snippets", function () {
StackExchange.snippets.init();
});
});
}, "code-snippets");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "1"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
draft saved
draft discarded
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53457733%2fusing-lodash-groupby-to-normalise-objects%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
1
A way without using lodash or ramda could be this. Hope this helps.
const input= [{
countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 142,
studentName: "Mary"
}, {
countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 145,
studentName: "John"
}, {
countryID: 14,
country: "UK",
schoolID: 222,
schoolZone: "Leeds",
studentID: 223,
studentName: "Peter"
}];
const normalize = (data) =>
data.reduce((acc, { studentID, studentName, schoolID, schoolZone, countryID, country }) => {
const studentToAdd = { studentID, studentName };
const schoolToAdd = { schoolID, schoolZone, students: [studentToAdd] };
const countryToAdd = { countryID, country, schools: [schoolToAdd] };
const existingCountry = acc.find(item => item.countryID === countryID);
if (existingCountry) {
const existingSchool = existingCountry.schools.find(item => item.schoolID === schoolID);
if (existingSchool) {
const existingStudent = existingSchool.students.find(item => item.studentID === studentID);
if (!existingStudent) existingSchool.students.push(studentToAdd);
}
else existingCountry.schools.push(schoolToAdd);
}
else acc.push(countryToAdd);
return acc;
}, );
console.log(normalize(input));answered Nov 24 '18 at 15:09
Alex GAlex G
1,221139
add a comment |
1
A way without using lodash or ramda could be this. Hope this helps.
const input= [{
countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 142,
studentName: "Mary"
}, {
countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 145,
studentName: "John"
}, {
countryID: 14,
country: "UK",
schoolID: 222,
schoolZone: "Leeds",
studentID: 223,
studentName: "Peter"
}];
const normalize = (data) =>
data.reduce((acc, { studentID, studentName, schoolID, schoolZone, countryID, country }) => {
const studentToAdd = { studentID, studentName };
const schoolToAdd = { schoolID, schoolZone, students: [studentToAdd] };
const countryToAdd = { countryID, country, schools: [schoolToAdd] };
const existingCountry = acc.find(item => item.countryID === countryID);
if (existingCountry) {
const existingSchool = existingCountry.schools.find(item => item.schoolID === schoolID);
if (existingSchool) {
const existingStudent = existingSchool.students.find(item => item.studentID === studentID);
if (!existingStudent) existingSchool.students.push(studentToAdd);
}
else existingCountry.schools.push(schoolToAdd);
}
else acc.push(countryToAdd);
return acc;
}, );
console.log(normalize(input));answered Nov 24 '18 at 15:09
Alex GAlex G
1,221139
add a comment |
1
1
1
A way without using lodash or ramda could be this. Hope this helps.
const input= [{
countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 142,
studentName: "Mary"
}, {
countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 145,
studentName: "John"
}, {
countryID: 14,
country: "UK",
schoolID: 222,
schoolZone: "Leeds",
studentID: 223,
studentName: "Peter"
}];
const normalize = (data) =>
data.reduce((acc, { studentID, studentName, schoolID, schoolZone, countryID, country }) => {
const studentToAdd = { studentID, studentName };
const schoolToAdd = { schoolID, schoolZone, students: [studentToAdd] };
const countryToAdd = { countryID, country, schools: [schoolToAdd] };
const existingCountry = acc.find(item => item.countryID === countryID);
if (existingCountry) {
const existingSchool = existingCountry.schools.find(item => item.schoolID === schoolID);
if (existingSchool) {
const existingStudent = existingSchool.students.find(item => item.studentID === studentID);
if (!existingStudent) existingSchool.students.push(studentToAdd);
}
else existingCountry.schools.push(schoolToAdd);
}
else acc.push(countryToAdd);
return acc;
}, );
console.log(normalize(input));answered Nov 24 '18 at 15:09
Alex GAlex G
1,221139
A way without using lodash or ramda could be this. Hope this helps.
const input= [{
countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 142,
studentName: "Mary"
}, {
countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 145,
studentName: "John"
}, {
countryID: 14,
country: "UK",
schoolID: 222,
schoolZone: "Leeds",
studentID: 223,
studentName: "Peter"
}];
const normalize = (data) =>
data.reduce((acc, { studentID, studentName, schoolID, schoolZone, countryID, country }) => {
const studentToAdd = { studentID, studentName };
const schoolToAdd = { schoolID, schoolZone, students: [studentToAdd] };
const countryToAdd = { countryID, country, schools: [schoolToAdd] };
const existingCountry = acc.find(item => item.countryID === countryID);
if (existingCountry) {
const existingSchool = existingCountry.schools.find(item => item.schoolID === schoolID);
if (existingSchool) {
const existingStudent = existingSchool.students.find(item => item.studentID === studentID);
if (!existingStudent) existingSchool.students.push(studentToAdd);
}
else existingCountry.schools.push(schoolToAdd);
}
else acc.push(countryToAdd);
return acc;
}, );
console.log(normalize(input));const input= [{
countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 142,
studentName: "Mary"
}, {
countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 145,
studentName: "John"
}, {
countryID: 14,
country: "UK",
schoolID: 222,
schoolZone: "Leeds",
studentID: 223,
studentName: "Peter"
}];
const normalize = (data) =>
data.reduce((acc, { studentID, studentName, schoolID, schoolZone, countryID, country }) => {
const studentToAdd = { studentID, studentName };
const schoolToAdd = { schoolID, schoolZone, students: [studentToAdd] };
const countryToAdd = { countryID, country, schools: [schoolToAdd] };
const existingCountry = acc.find(item => item.countryID === countryID);
if (existingCountry) {
const existingSchool = existingCountry.schools.find(item => item.schoolID === schoolID);
if (existingSchool) {
const existingStudent = existingSchool.students.find(item => item.studentID === studentID);
if (!existingStudent) existingSchool.students.push(studentToAdd);
}
else existingCountry.schools.push(schoolToAdd);
}
else acc.push(countryToAdd);
return acc;
}, );
console.log(normalize(input));const input= [{
countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 142,
studentName: "Mary"
}, {
countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 145,
studentName: "John"
}, {
countryID: 14,
country: "UK",
schoolID: 222,
schoolZone: "Leeds",
studentID: 223,
studentName: "Peter"
}];
const normalize = (data) =>
data.reduce((acc, { studentID, studentName, schoolID, schoolZone, countryID, country }) => {
const studentToAdd = { studentID, studentName };
const schoolToAdd = { schoolID, schoolZone, students: [studentToAdd] };
const countryToAdd = { countryID, country, schools: [schoolToAdd] };
const existingCountry = acc.find(item => item.countryID === countryID);
if (existingCountry) {
const existingSchool = existingCountry.schools.find(item => item.schoolID === schoolID);
if (existingSchool) {
const existingStudent = existingSchool.students.find(item => item.studentID === studentID);
if (!existingStudent) existingSchool.students.push(studentToAdd);
}
else existingCountry.schools.push(schoolToAdd);
}
else acc.push(countryToAdd);
return acc;
}, );
console.log(normalize(input));answered Nov 24 '18 at 15:09
Alex GAlex G
1,221139
answered Nov 24 '18 at 15:09
Alex GAlex G
1,221139
answered Nov 24 '18 at 15:09
Alex GAlex G
1,221139
answered Nov 24 '18 at 15:09
Alex GAlex G
1,221139
1,221139
add a comment |
add a comment |
1
With lodash you can solve this in the following concise way:
const data = [{ countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 142, studentName: "Mary" }, { countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 145, studentName: "John" }, { countryID: 14, country: "UK", schoolID: 222, schoolZone: "Leeds", studentID: 223, studentName: "Peter" } ];
const grp = (arr, key, field, group, o=0) => _(arr)
.groupBy(key)
.mapValues(x => ({
[key]: _.head(x)[key],
[field]: _.head(x)[field],
[group]: o
? _.map(x, s => _.pick(s, ['studentID', 'studentName']))
: grp(x, 'schoolID', 'schoolZone', 'students', 1)
}))
.values()
.value()
console.log(grp(data, 'countryID', 'country', 'schools'))<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.10/lodash.min.js"></script>The idea is to use recursive approach where you call the same grouping function 2 times. Inside of which we would _.groupBy and just do _.mapValues
Now the exact same idea with compact ES6 code would look like:
const data = [{ countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 142, studentName: "Mary" }, { countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 145, studentName: "John" }, { countryID: 14, country: "UK", schoolID: 222, schoolZone: "Leeds", studentID: 223, studentName: "Peter" } ];
const groupBy = (arr, k) => arr.reduce((r,c) => (r[c[k]] = [...r[c[k]] || , c], r), {})
const pick = (obj, fields) => fields.reduce((r,f) => (r[f] = obj[f], r), {})
const grp = (arr, k, f, b, o=0) =>
Object.values(Object.values(groupBy(arr, k)).map(x => ({
[k]: x[0][k],
[f]: x[0][f],
[b]: o
? x.map(s => pick(s, ['studentID', 'studentName']))
: grp(x, 'schoolID', 'schoolZone', 'students', 1)
})))
console.log(grp(data, 'countryID', 'country', 'schools'))answered Nov 24 '18 at 23:25
AkrionAkrion
9,45511224
add a comment |
1
With lodash you can solve this in the following concise way:
const data = [{ countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 142, studentName: "Mary" }, { countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 145, studentName: "John" }, { countryID: 14, country: "UK", schoolID: 222, schoolZone: "Leeds", studentID: 223, studentName: "Peter" } ];
const grp = (arr, key, field, group, o=0) => _(arr)
.groupBy(key)
.mapValues(x => ({
[key]: _.head(x)[key],
[field]: _.head(x)[field],
[group]: o
? _.map(x, s => _.pick(s, ['studentID', 'studentName']))
: grp(x, 'schoolID', 'schoolZone', 'students', 1)
}))
.values()
.value()
console.log(grp(data, 'countryID', 'country', 'schools'))<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.10/lodash.min.js"></script>The idea is to use recursive approach where you call the same grouping function 2 times. Inside of which we would _.groupBy and just do _.mapValues
Now the exact same idea with compact ES6 code would look like:
const data = [{ countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 142, studentName: "Mary" }, { countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 145, studentName: "John" }, { countryID: 14, country: "UK", schoolID: 222, schoolZone: "Leeds", studentID: 223, studentName: "Peter" } ];
const groupBy = (arr, k) => arr.reduce((r,c) => (r[c[k]] = [...r[c[k]] || , c], r), {})
const pick = (obj, fields) => fields.reduce((r,f) => (r[f] = obj[f], r), {})
const grp = (arr, k, f, b, o=0) =>
Object.values(Object.values(groupBy(arr, k)).map(x => ({
[k]: x[0][k],
[f]: x[0][f],
[b]: o
? x.map(s => pick(s, ['studentID', 'studentName']))
: grp(x, 'schoolID', 'schoolZone', 'students', 1)
})))
console.log(grp(data, 'countryID', 'country', 'schools'))answered Nov 24 '18 at 23:25
AkrionAkrion
9,45511224
add a comment |
1
1
1
With lodash you can solve this in the following concise way:
const data = [{ countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 142, studentName: "Mary" }, { countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 145, studentName: "John" }, { countryID: 14, country: "UK", schoolID: 222, schoolZone: "Leeds", studentID: 223, studentName: "Peter" } ];
const grp = (arr, key, field, group, o=0) => _(arr)
.groupBy(key)
.mapValues(x => ({
[key]: _.head(x)[key],
[field]: _.head(x)[field],
[group]: o
? _.map(x, s => _.pick(s, ['studentID', 'studentName']))
: grp(x, 'schoolID', 'schoolZone', 'students', 1)
}))
.values()
.value()
console.log(grp(data, 'countryID', 'country', 'schools'))<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.10/lodash.min.js"></script>The idea is to use recursive approach where you call the same grouping function 2 times. Inside of which we would _.groupBy and just do _.mapValues
Now the exact same idea with compact ES6 code would look like:
const data = [{ countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 142, studentName: "Mary" }, { countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 145, studentName: "John" }, { countryID: 14, country: "UK", schoolID: 222, schoolZone: "Leeds", studentID: 223, studentName: "Peter" } ];
const groupBy = (arr, k) => arr.reduce((r,c) => (r[c[k]] = [...r[c[k]] || , c], r), {})
const pick = (obj, fields) => fields.reduce((r,f) => (r[f] = obj[f], r), {})
const grp = (arr, k, f, b, o=0) =>
Object.values(Object.values(groupBy(arr, k)).map(x => ({
[k]: x[0][k],
[f]: x[0][f],
[b]: o
? x.map(s => pick(s, ['studentID', 'studentName']))
: grp(x, 'schoolID', 'schoolZone', 'students', 1)
})))
console.log(grp(data, 'countryID', 'country', 'schools'))answered Nov 24 '18 at 23:25
AkrionAkrion
9,45511224
With lodash you can solve this in the following concise way:
const data = [{ countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 142, studentName: "Mary" }, { countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 145, studentName: "John" }, { countryID: 14, country: "UK", schoolID: 222, schoolZone: "Leeds", studentID: 223, studentName: "Peter" } ];
const grp = (arr, key, field, group, o=0) => _(arr)
.groupBy(key)
.mapValues(x => ({
[key]: _.head(x)[key],
[field]: _.head(x)[field],
[group]: o
? _.map(x, s => _.pick(s, ['studentID', 'studentName']))
: grp(x, 'schoolID', 'schoolZone', 'students', 1)
}))
.values()
.value()
console.log(grp(data, 'countryID', 'country', 'schools'))<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.10/lodash.min.js"></script>The idea is to use recursive approach where you call the same grouping function 2 times. Inside of which we would _.groupBy and just do _.mapValues
Now the exact same idea with compact ES6 code would look like:
const data = [{ countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 142, studentName: "Mary" }, { countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 145, studentName: "John" }, { countryID: 14, country: "UK", schoolID: 222, schoolZone: "Leeds", studentID: 223, studentName: "Peter" } ];
const groupBy = (arr, k) => arr.reduce((r,c) => (r[c[k]] = [...r[c[k]] || , c], r), {})
const pick = (obj, fields) => fields.reduce((r,f) => (r[f] = obj[f], r), {})
const grp = (arr, k, f, b, o=0) =>
Object.values(Object.values(groupBy(arr, k)).map(x => ({
[k]: x[0][k],
[f]: x[0][f],
[b]: o
? x.map(s => pick(s, ['studentID', 'studentName']))
: grp(x, 'schoolID', 'schoolZone', 'students', 1)
})))
console.log(grp(data, 'countryID', 'country', 'schools'))const data = [{ countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 142, studentName: "Mary" }, { countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 145, studentName: "John" }, { countryID: 14, country: "UK", schoolID: 222, schoolZone: "Leeds", studentID: 223, studentName: "Peter" } ];
const grp = (arr, key, field, group, o=0) => _(arr)
.groupBy(key)
.mapValues(x => ({
[key]: _.head(x)[key],
[field]: _.head(x)[field],
[group]: o
? _.map(x, s => _.pick(s, ['studentID', 'studentName']))
: grp(x, 'schoolID', 'schoolZone', 'students', 1)
}))
.values()
.value()
console.log(grp(data, 'countryID', 'country', 'schools'))<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.10/lodash.min.js"></script>const data = [{ countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 142, studentName: "Mary" }, { countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 145, studentName: "John" }, { countryID: 14, country: "UK", schoolID: 222, schoolZone: "Leeds", studentID: 223, studentName: "Peter" } ];
const grp = (arr, key, field, group, o=0) => _(arr)
.groupBy(key)
.mapValues(x => ({
[key]: _.head(x)[key],
[field]: _.head(x)[field],
[group]: o
? _.map(x, s => _.pick(s, ['studentID', 'studentName']))
: grp(x, 'schoolID', 'schoolZone', 'students', 1)
}))
.values()
.value()
console.log(grp(data, 'countryID', 'country', 'schools'))<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.10/lodash.min.js"></script>const data = [{ countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 142, studentName: "Mary" }, { countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 145, studentName: "John" }, { countryID: 14, country: "UK", schoolID: 222, schoolZone: "Leeds", studentID: 223, studentName: "Peter" } ];
const groupBy = (arr, k) => arr.reduce((r,c) => (r[c[k]] = [...r[c[k]] || , c], r), {})
const pick = (obj, fields) => fields.reduce((r,f) => (r[f] = obj[f], r), {})
const grp = (arr, k, f, b, o=0) =>
Object.values(Object.values(groupBy(arr, k)).map(x => ({
[k]: x[0][k],
[f]: x[0][f],
[b]: o
? x.map(s => pick(s, ['studentID', 'studentName']))
: grp(x, 'schoolID', 'schoolZone', 'students', 1)
})))
console.log(grp(data, 'countryID', 'country', 'schools'))const data = [{ countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 142, studentName: "Mary" }, { countryID: 12, country: "US", schoolID: 122, schoolZone: "Highlands", studentID: 145, studentName: "John" }, { countryID: 14, country: "UK", schoolID: 222, schoolZone: "Leeds", studentID: 223, studentName: "Peter" } ];
const groupBy = (arr, k) => arr.reduce((r,c) => (r[c[k]] = [...r[c[k]] || , c], r), {})
const pick = (obj, fields) => fields.reduce((r,f) => (r[f] = obj[f], r), {})
const grp = (arr, k, f, b, o=0) =>
Object.values(Object.values(groupBy(arr, k)).map(x => ({
[k]: x[0][k],
[f]: x[0][f],
[b]: o
? x.map(s => pick(s, ['studentID', 'studentName']))
: grp(x, 'schoolID', 'schoolZone', 'students', 1)
})))
console.log(grp(data, 'countryID', 'country', 'schools'))answered Nov 24 '18 at 23:25
AkrionAkrion
9,45511224
edited Nov 24 '18 at 23:38
answered Nov 24 '18 at 23:25
AkrionAkrion
9,45511224
answered Nov 24 '18 at 23:25
AkrionAkrion
9,45511224
answered Nov 24 '18 at 23:25
AkrionAkrion
9,45511224
9,45511224
add a comment |
add a comment |
0
First reshape each object to look like the final data structure:
reshape({
countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 142,
studentName: "Mary" });
//=> {
//=> country: "US",
//=> countryID: 12,
//=> schools: [
//=> {
//=> schoolID: 122,
//=> schoolZone: "Highlands",
//=> students: [
//=> {
//=> studentID: 142,
//=> studentName: "Mary"
//=> }
//=> ]
//=> }
//=> ]
//=> }
Then it is simply a matter of grouping by countries then by schools and using a map & reduce function to merge objects.
const {pick, map, groupBy, values, lensProp, over, reduce, mergeWithKey, pipe, prop, applySpec, converge, set, of} = R;
const input = [
{ countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 142,
studentName: "Mary" },
{ countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 145,
studentName: "John" },
{ countryID: 14,
country: "UK",
schoolID: 222,
schoolZone: "Leeds",
studentID: 223,
studentName: "Peter" }];
const reshape = applySpec({
countryID: prop('countryID'),
country: prop('country'),
schools: converge(
pipe(set(lensProp('students')), of), [
pipe(pick(['studentID', 'studentName']), of),
pick(['schoolID', 'schoolZone'])])
});
const mergeArrays = key => mergeWithKey((k, a, b) => k === key ? [a[0], b[0]] : a);
const groupStudents = pipe(
groupBy(prop('schoolID')),
values,
map(reduce(mergeArrays('students'), {})));
const process = pipe(
map(reshape),
groupBy(prop('countryID')),
map(reduce(mergeArrays('schools'), {})),
map(over(lensProp('schools'), groupStudents)),
values);
console.log(process(input));<script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.25.0/ramda.min.js"></script>answered Nov 24 '18 at 13:47
customcommandercustomcommander
1,73111019
add a comment |
0
First reshape each object to look like the final data structure:
reshape({
countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 142,
studentName: "Mary" });
//=> {
//=> country: "US",
//=> countryID: 12,
//=> schools: [
//=> {
//=> schoolID: 122,
//=> schoolZone: "Highlands",
//=> students: [
//=> {
//=> studentID: 142,
//=> studentName: "Mary"
//=> }
//=> ]
//=> }
//=> ]
//=> }
Then it is simply a matter of grouping by countries then by schools and using a map & reduce function to merge objects.
const {pick, map, groupBy, values, lensProp, over, reduce, mergeWithKey, pipe, prop, applySpec, converge, set, of} = R;
const input = [
{ countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 142,
studentName: "Mary" },
{ countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 145,
studentName: "John" },
{ countryID: 14,
country: "UK",
schoolID: 222,
schoolZone: "Leeds",
studentID: 223,
studentName: "Peter" }];
const reshape = applySpec({
countryID: prop('countryID'),
country: prop('country'),
schools: converge(
pipe(set(lensProp('students')), of), [
pipe(pick(['studentID', 'studentName']), of),
pick(['schoolID', 'schoolZone'])])
});
const mergeArrays = key => mergeWithKey((k, a, b) => k === key ? [a[0], b[0]] : a);
const groupStudents = pipe(
groupBy(prop('schoolID')),
values,
map(reduce(mergeArrays('students'), {})));
const process = pipe(
map(reshape),
groupBy(prop('countryID')),
map(reduce(mergeArrays('schools'), {})),
map(over(lensProp('schools'), groupStudents)),
values);
console.log(process(input));<script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.25.0/ramda.min.js"></script>answered Nov 24 '18 at 13:47
customcommandercustomcommander
1,73111019
add a comment |
0
0
0
First reshape each object to look like the final data structure:
reshape({
countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 142,
studentName: "Mary" });
//=> {
//=> country: "US",
//=> countryID: 12,
//=> schools: [
//=> {
//=> schoolID: 122,
//=> schoolZone: "Highlands",
//=> students: [
//=> {
//=> studentID: 142,
//=> studentName: "Mary"
//=> }
//=> ]
//=> }
//=> ]
//=> }
Then it is simply a matter of grouping by countries then by schools and using a map & reduce function to merge objects.
const {pick, map, groupBy, values, lensProp, over, reduce, mergeWithKey, pipe, prop, applySpec, converge, set, of} = R;
const input = [
{ countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 142,
studentName: "Mary" },
{ countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 145,
studentName: "John" },
{ countryID: 14,
country: "UK",
schoolID: 222,
schoolZone: "Leeds",
studentID: 223,
studentName: "Peter" }];
const reshape = applySpec({
countryID: prop('countryID'),
country: prop('country'),
schools: converge(
pipe(set(lensProp('students')), of), [
pipe(pick(['studentID', 'studentName']), of),
pick(['schoolID', 'schoolZone'])])
});
const mergeArrays = key => mergeWithKey((k, a, b) => k === key ? [a[0], b[0]] : a);
const groupStudents = pipe(
groupBy(prop('schoolID')),
values,
map(reduce(mergeArrays('students'), {})));
const process = pipe(
map(reshape),
groupBy(prop('countryID')),
map(reduce(mergeArrays('schools'), {})),
map(over(lensProp('schools'), groupStudents)),
values);
console.log(process(input));<script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.25.0/ramda.min.js"></script>answered Nov 24 '18 at 13:47
customcommandercustomcommander
1,73111019
First reshape each object to look like the final data structure:
reshape({
countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 142,
studentName: "Mary" });
//=> {
//=> country: "US",
//=> countryID: 12,
//=> schools: [
//=> {
//=> schoolID: 122,
//=> schoolZone: "Highlands",
//=> students: [
//=> {
//=> studentID: 142,
//=> studentName: "Mary"
//=> }
//=> ]
//=> }
//=> ]
//=> }
Then it is simply a matter of grouping by countries then by schools and using a map & reduce function to merge objects.
const {pick, map, groupBy, values, lensProp, over, reduce, mergeWithKey, pipe, prop, applySpec, converge, set, of} = R;
const input = [
{ countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 142,
studentName: "Mary" },
{ countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 145,
studentName: "John" },
{ countryID: 14,
country: "UK",
schoolID: 222,
schoolZone: "Leeds",
studentID: 223,
studentName: "Peter" }];
const reshape = applySpec({
countryID: prop('countryID'),
country: prop('country'),
schools: converge(
pipe(set(lensProp('students')), of), [
pipe(pick(['studentID', 'studentName']), of),
pick(['schoolID', 'schoolZone'])])
});
const mergeArrays = key => mergeWithKey((k, a, b) => k === key ? [a[0], b[0]] : a);
const groupStudents = pipe(
groupBy(prop('schoolID')),
values,
map(reduce(mergeArrays('students'), {})));
const process = pipe(
map(reshape),
groupBy(prop('countryID')),
map(reduce(mergeArrays('schools'), {})),
map(over(lensProp('schools'), groupStudents)),
values);
console.log(process(input));<script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.25.0/ramda.min.js"></script>const {pick, map, groupBy, values, lensProp, over, reduce, mergeWithKey, pipe, prop, applySpec, converge, set, of} = R;
const input = [
{ countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 142,
studentName: "Mary" },
{ countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 145,
studentName: "John" },
{ countryID: 14,
country: "UK",
schoolID: 222,
schoolZone: "Leeds",
studentID: 223,
studentName: "Peter" }];
const reshape = applySpec({
countryID: prop('countryID'),
country: prop('country'),
schools: converge(
pipe(set(lensProp('students')), of), [
pipe(pick(['studentID', 'studentName']), of),
pick(['schoolID', 'schoolZone'])])
});
const mergeArrays = key => mergeWithKey((k, a, b) => k === key ? [a[0], b[0]] : a);
const groupStudents = pipe(
groupBy(prop('schoolID')),
values,
map(reduce(mergeArrays('students'), {})));
const process = pipe(
map(reshape),
groupBy(prop('countryID')),
map(reduce(mergeArrays('schools'), {})),
map(over(lensProp('schools'), groupStudents)),
values);
console.log(process(input));<script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.25.0/ramda.min.js"></script>const {pick, map, groupBy, values, lensProp, over, reduce, mergeWithKey, pipe, prop, applySpec, converge, set, of} = R;
const input = [
{ countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 142,
studentName: "Mary" },
{ countryID: 12,
country: "US",
schoolID: 122,
schoolZone: "Highlands",
studentID: 145,
studentName: "John" },
{ countryID: 14,
country: "UK",
schoolID: 222,
schoolZone: "Leeds",
studentID: 223,
studentName: "Peter" }];
const reshape = applySpec({
countryID: prop('countryID'),
country: prop('country'),
schools: converge(
pipe(set(lensProp('students')), of), [
pipe(pick(['studentID', 'studentName']), of),
pick(['schoolID', 'schoolZone'])])
});
const mergeArrays = key => mergeWithKey((k, a, b) => k === key ? [a[0], b[0]] : a);
const groupStudents = pipe(
groupBy(prop('schoolID')),
values,
map(reduce(mergeArrays('students'), {})));
const process = pipe(
map(reshape),
groupBy(prop('countryID')),
map(reduce(mergeArrays('schools'), {})),
map(over(lensProp('schools'), groupStudents)),
values);
console.log(process(input));<script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.25.0/ramda.min.js"></script>answered Nov 24 '18 at 13:47
customcommandercustomcommander
1,73111019
edited Nov 25 '18 at 1:45
answered Nov 24 '18 at 13:47
customcommandercustomcommander
1,73111019
answered Nov 24 '18 at 13:47
customcommandercustomcommander
1,73111019
answered Nov 24 '18 at 13:47
customcommandercustomcommander
1,73111019
1,73111019
add a comment |
add a comment |
draft saved
draft discarded
Thanks for contributing an answer to Stack Overflow!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
draft saved
draft discarded
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53457733%2fusing-lodash-groupby-to-normalise-objects%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
