How can we change the structure of the below data object using JavaScript. Needs to categorize all the names under the std. Thanks in advance
[
{
"name": "Rohan",
"std": "3"
},
{
"name": "Jack",
"std": "2"
},
{
"name": "Peter",
"std": "2"
}
]
to
[
{
"std": "2",
"details": [
{
"name": "Jack"
},
{
"name": "Peter"
}
]
},
{
"std": "3",
"details": [
{
"name": "Rohan"
}
]
}
]
The solution using Array.forEach, Array.map and Object.keys functions:
var arr = [{"name": "Rohan", "std": "3"}, { "name": "Jack", "std": "2" }, { "name": "Peter", "std": "2" }],
grouped = {}, result;
arr.forEach(function(obj){
var std = obj['std'];
if (this[std]) {
this[std]['details'].push({'name' : obj['name']});
} else {
this[std] = {'std' : std, 'details' : [{'name' : obj['name']}]};
}
}, grouped);
result = Object.keys(grouped).map((k) => grouped[k]);
console.log(JSON.stringify(result, 0, 4));
The output:
[
{
"std": "2",
"details": [
{
"name": "Jack"
},
{
"name": "Peter"
}
]
},
{
"std": "3",
"details": [
{
"name": "Rohan"
}
]
}
]
You can use reduce() method here
var data = [{
"name": "Rohan",
"std": "3"
}, {
"name": "Jack",
"std": "2"
}, {
"name": "Peter",
"std": "2"
}],
res = [],
kmap = {};
res = data.reduce(function(a, b) {
// check std value already in array using kmap object
if (kmap[b.std]) {
// if already exist then push name attribute in the details
a[kmap[b.std] - 1].details.push({
'name': b.name
});
} else {
// in else case push the new object
a.push({
'std': b.std,
'details': [{
'name': b.name
}]
});
kmap[b.std] = a.length; // storing the (index + 1) value to avoid 0 in if condition
}
return a;
}, []);
console.log(res);
For older browsers check polyfill option for reduce method.
Problems like this are good candidates for recursion. Here is one possible recursive solution. You can make it much prettier using a functional programming framework such as underscore.js.
var objs = [
{
"name": "Rohan",
"std": "3"
},
{
"name": "Jack",
"std": "2"
},
{
"name": "Peter",
"std": "2"
}
];
function categorize(objs) {
if (objs.length === 0) {
return [];
} else {
var first = objs.shift();
var categorized = categorize(objs);
for(var i = 0; i < categorized.length; i++) {
if (categorized[i].std === first.std) {
categorized[i].details.push({name: first.name});
break;
}
}
if(i === categorized.length) {
categorized.push({std: first.std, details: [{name: first.name}]});
}
return categorized;
}
}
var res = categorize(objs);
console.log(res);
If you're using lodash (I know the question didn't ask this and it's going to be slower, but it may be useful to someone :))
var data = [
{ "name": "Rohan", "std": "3" },
{ "name": "Jack", "std": "2" },
{ "name": "Peter", "std": "2" }
];
var grouped = _.chain(data)
.groupBy('std')
.map(function (people, std) {
return {
std: std,
details: _.map(people, function(person) {
return { name: person.name };
})
}
}).value();
Related
I have a nested array like below. There are about 100 de objects in the array. The de objects also have deg[0] array but most likely I will only have the first index. Now the trick is that the de are subset of deg. Which means each deg can have say 10 de. How can I retrieve the deg and there associated de and map it into a new array like:
newArray = [
deg1: [
{de1},
{de2}
],
deg2: [
{de1},
{de2}
]
]
Here is my nested array. I posted four but the list is over a 100.
{
"name": "Report",
"id": "2YYUEZ6I1r9",
"dse1": [
{
"de1": {
"name": "Number",
"id": "HjMOngg3kuy",
"de1-av": [
{
"value": "FHaQMPv9zc7",
"attribute": {
"id": "uwVkIP7PZDt"
}
},
{
"value": "something",
"attribute": {
"id": "FHaQMPv9zc7"
}
}
],
"deg1": [
{
"name": "TB",
"id": "2XJB1JO9qX8"
}
]
}
},
{
"de2": {
"name": "Number of",
"id": "a3dtGETTawy",
"de2-av": [
{
"value": "FHaQMPv9zc7",
"attribute": {
"id": "uwVkIP7PZDt"
}
},
{
"value": "something",
"attribute": {
"id": "FHaQMPv9zc7"
}
}
],
"deg1": [
{
"name": "Secondary",
"id": "w99RWzXHgtw"
}
]
}
},
{
"de1": {
"name": "Number of",
"id": "a3dtGETTawy",
"de1av": [
{
"value": "FHaQMPv9zc7",
"attribute": {
"id": "uwVkIP7PZDt"
}
},
{
"value": "something",
"attribute": {
"id": "FHaQMPv9zc7"
}
}
],
"deg2": [
{
"name": "Secondary",
"id": "w99RWzXHgtw"
}
]
}
},
{
"de2": {
"name": "Number of",
"id": "a3dtGETTawy",
"de2av": [
{
"value": "FHaQMPv9zc7",
"attribute": {
"id": "uwVkIP7PZDt"
}
},
{
"value": "something",
"attribute": {
"id": "FHaQMPv9zc7"
}
}
],
"deg2": [
{
"name": "Tertiary",
"id": "w99RWzXHgtw"
}
]
}
}
]
}
Group array of objects by property (this time a property to be matched by a reg exp) using Array.reduce.
Update: Ignoring missing keys.
var input={name:"Report",id:"2YYUEZ6I1r9",dse1:[{de1:{name:"Number",id:"HjMOngg3kuy","de1-av":[{value:"FHaQMPv9zc7",attribute:{id:"uwVkIP7PZDt"}},{value:"something",attribute:{id:"FHaQMPv9zc7"}}],deg1:[{name:"TB",id:"2XJB1JO9qX8"}]}},{de2:{name:"Number of",id:"a3dtGETTawy","de2-av":[{value:"FHaQMPv9zc7",attribute:{id:"uwVkIP7PZDt"}},{value:"something",attribute:{id:"FHaQMPv9zc7"}}],deg1:[{name:"Secondary",id:"w99RWzXHgtw"}]}},{de1:{name:"Number of",id:"a3dtGETTawy",de1av:[{value:"FHaQMPv9zc7",attribute:{id:"uwVkIP7PZDt"}},{value:"something",attribute:{id:"FHaQMPv9zc7"}}],deg2:[{name:"Secondary",id:"w99RWzXHgtw"}]}},{de2:{name:"Number of",id:"a3dtGETTawy",de2av:[{value:"FHaQMPv9zc7",attribute:{id:"uwVkIP7PZDt"}},{value:"something",attribute:{id:"FHaQMPv9zc7"}}],deg2:[{name:"Tertiary",id:"w99RWzXHgtw"}]}}]}
var reg = new RegExp("^de[0-9]+$");
var reg2 = new RegExp("^deg[0-9]+$");
let obj = input['dse1'].reduce(function(agg, item) {
// do your group by logic below this line
var key = Object.keys(item).find(function(key) {
return key.match(reg) ? key : null;
})
if (key) {
var key2 = Object.keys(item[key]).find(function(key) {
return key.match(reg2) ? key : null;
})
agg[key] = agg[key] || [];
if (key2) {
var to_push = {}
to_push[key2] = item[key][key2]
agg[key].push(to_push)
}
}
// do your group by logic above this line
return agg
}, {});
console.log(obj)
.as-console-wrapper {
max-height: 100% !important;
}
I have below dynamic nested JSON object arrays and I wanted to get the desired output with JavaScript grouped by id from both.
First Array:
[
{
"id": "11",
"name": "emp1",
"location": [
{ "name": "abc", "id": "lc1" }
]
},
{
"id": "11",
"name": "emp2",
"location": [
{ "name": "abc", "id": "lc1" },
]
},
{
"id": "22",
"name": "emp3",
"location": [
{ "name": "xyz", "id": "lc2" }
]
}
]
Second array like below.
[
{
"name": "sub1",
"id": "11"
...
},
{
"name": "sub1.1",
"id": "11"
...
},
{
"name": "sub2",
"id": "22"
...
}
]
Desired Output:
[
{
"id": "11",
"first": [{"name": "emp1"},
{"name": "emp2"}],
"second": [{"name": "sub1"},{"name": "sub1.1"}],
"location": [{"name": "abc"}]
},
{
"id": "22",
"first": [{"name": "emp3"}],
"second": [{"name": "sub2"}],
"location": [{"name": "xyz"}]
}
]
How to get the desired output like above using javascript/angularjs?
I would do it using the amazing Array#reduce function.
Note that I have named your first array as a1, second as a2 and result as res.
a1.reduce(function(arr, obj) {
var existing = arr.filter(function(res) {
return res.id === obj.id
})[0]
if (existing) {
existing.first.push({
name: obj.name
})
} else {
var second = a2.filter(function(res) {
return res.id === obj.id
})
var secondObj = second.length ? second.map(function(sec) {
return {
name: sec.name
};
}) : []
arr.push({
id: obj.id,
first: [{
name: obj.name
}],
second: secondObj,
location: obj.location
})
}
return arr;
}, [])
Here's the working snippet. Take a look!
var a1 = [{
"id": "11",
"name": "emp1",
"location": [{
"name": "abc",
"id": "lc1"
}]
},
{
"id": "11",
"name": "emp2",
"location": [{
"name": "abc",
"id": "lc1"
}]
},
{
"id": "22",
"name": "emp3",
"location": [{
"name": "xyz",
"id": "lc2"
}]
}
]
var a2 = [{
"name": "sub1",
"id": "11"
}, {
"name": "sub1.1",
"id": "11"
},
{
"name": "sub2",
"id": "22"
}
]
var res = a1.reduce(function(arr, obj) {
var existing = arr.filter(function(res) {
return res.id === obj.id
})[0]
if (existing) {
existing.first.push({
name: obj.name
})
} else {
var second = a2.filter(function(res) {
return res.id === obj.id
})
var secondObj = second.length ? second.map(function(sec) {
return {
name: sec.name
};
}) : []
arr.push({
id: obj.id,
first: [{
name: obj.name
}],
second: secondObj,
location: obj.location
})
}
return arr;
}, [])
console.log(res)
.as-console-wrapper {
max-height: 100% !important;
top: 0;
}
var red1 = [{
"id": "11",
"name": "emp1",
"location": [{
"name": "abc",
"id": "lc1"
}]
},
{
"id": "11",
"name": "emp2",
"location": [{
"name": "abc",
"id": "lc1"
}]
},
{
"id": "22",
"name": "emp3",
"location": [{
"name": "xyz",
"id": "lc2"
}]
}
]
var b = [{
"name": "sub1",
"id": "11"
},
{
"name": "sub2",
"id": "22"
}
]
var identication = {}
var result = []
red1.forEach(function(val) {
if (val['id'] in identication) {
var t = {}
t['name'] = val['name']
result[identication[val['id']]]['first'].push(t)
} else {
var t = {}
t['name'] = val['name']
val['first'] = []
val['first'].push(t)
delete val['name']
var identity = result.push(val)
identication[val['id']] = identity - 1;
}
})
b.forEach(function(d) {
if (d['id'] in identication) {
var t = {
'name': d['name']
}
if (!('second' in result[identication[d['id']]])) {
result[identication[d['id']]]['second'] = []
}
result[identication[d['id']]]['second'].push(t)
} else {
var t = {}
for (key in d) {
if (key == 'name')
continue
t[key] = d[key]
}
t['second'] = [{
'name': d['name']
}]
var identity = result.push(t)
identication[d['id']] = identity - 1;
}
})
console.log(result)
I have mongo document called groups. This is array of students and subjects.
Each subject has an array of lessons.
Each lesson has an array of marks.
Generally, document looks like this:
[
{
"students": [
{ "_id": "0", "firstName": "Bob", "lastName": "Jhonson" },
{ "_id": "1", "firstName": "Jackie", "lastName": "Chan" }
// other students ...
],
"subjects": [
{
"name": "Algebra",
"lessons": [
{
"date": 1489363200,
"marks": [
{ "student_id": "0", "value": 5 },
{ "student_id": "1", "value": 4 }
// other marks...
]
}, {
"date": 1489622400,
"marks": [
{ "student_id": "0", "value": 3 },
{ "student_id": "1", "value": 2 }
// other marks...
]
}
// other lessons...
]
}
]
}
]
Then I use js function to transform this data to something like this:
[
{
"_id": "5a89ca11abc4ffd25a430420",
"subjects": [
{
"name": "Algebra",
"dates": [1489363200, 1489622400],
"students": [
{
"_id": "0",
"firstName": "Bob",
"lastName": "Jhonson",
"marks": [ 5, 3 ]
},
{
"_id": "1",
"firstName": "Jackie",
"lastName": "Chan",
"marks": [ 4, 2 ]
}
]
}
]
}
]
Function which transforms json document:
function transformData (groups) { // groups - array
let newGroups = [];
for (let group of groups) {
newGroup = {};
for (let key in group) {
if (key === 'students' || key === 'subjects') continue;
newGroup[key] = group[key];
}
newGroup.subjects = [];
for (let subject of group.subjects) {
let newSubject = {
name: subject.name,
dates: [],
students: []
};
for (let student of group.students) {
let index = newSubject.students.push(student) - 1;
newSubject.students[index].marks = [];
}
for (let lesson of subject.lessons) {
let index = newSubject.dates.push(lesson.date) - 1;
for (let mark of lesson.marks) {
for (let student of newSubject.students) {
if (student._id !== mark.student_id) continue;
while(student.marks.length !== index) {
student.marks.push(null);
}
student.marks.push(mark.value);
}
}
}
newGroup.subjects.push(newSubject);
}
newGroups.push(newGroup);
}
return newGroups;
}
How can I replace this function with mongodb aggregation?
I want to build an new JSON from existing one. The source has sections and rubrics that I no longer need for a listing. The new object called 'items' should have an array of the items.
The final JSON should be sorted by attribute 'name' and look like
{
"items": [
{
"id": 10000006,
"name": "Boah"
},
{
"id": 10000013,
"name": "Gut"
},
{
"id": 10000003,
"name": "Ipsum"
},
{
"id": 10000001,
"name": "Lorem"
},
{
"id": 10000005,
"name": "Lorum"
},
{
"id": 10000004,
"name": "Name"
},
{
"id": 10000002,
"name": "Stet"
}
]
}
For building the new JSON I get this source:
{
"sections": [
{
"name": "FooBar",
"rubrics": [
{
"name": "Foo",
"items": [
{
"id": 10000001,
"name": "Lorem"
},
{
"id": 10000002,
"name": "Stet"
},
{
"id": 10000003,
"name": "Ipsum"
}
]
},
{
"name": "Bar",
"items": [
{
"id": 10000004,
"name": "Name"
},
{
"id": 10000005,
"name": "Lorum"
},
{
"id": 10000006,
"name": "Boah"
}
]
}
]
},
{
"name": "BlahBloob",
"rubrics": [
{
"name": "Bla",
"items": [
{
"id": 10000013,
"name": "Gut"
}
]
},
{
"name": "Bloob",
"items": [
{
"id": 10000014,
"name": "Name"
},
{
"id": 10000015,
"name": "Lorem"
}
]
}
]
}
]
}
What do you think? How can I do this with plain JavaScript or maybe TypeScript?
Thanks for reading and have time for my question. And thanks for reply in advance.
Here you go. You just need to iterate over each rubric of each section of your source to get the items. At the end, sort your list of items by items, and you're done.
This example uses ES6 syntax, but it's easy to convert it to ES5 if needed.
function extractItems(source) {
const items = [];
for (const section of source.sections) {
for (const rubric of section.rubrics) {
items.push(...rubric.items);
}
}
items.sort((a, b) => a.name.localeCompare(b.name));
return { items };
}
A more functional approach use map and reduce to pick the rubrics and merge them.
data.sections
.map(section => section.rubrics) // get rubrics
.reduce((a, b) => a.concat(b)) // merge rubrics
.map(rubric => rubric.items) // get items from each rubric
.reduce((a, b) => a.concat(b)) // merge items
.sort((a, b) => a.name.localeCompare(b.name)); // sort
function(oldObj) {
var newObj = {
"items": []
};
oldObj.sections.forEach(function(section) {
section.rubrics.forEach(function(rubric) {
rubric.items.forEach(function(item) {
newObj.items.push(item);
});
});
});
newObj.items = newObj.items.sort(function(a, b) {
if (a.name < b.name) { return -1; }
if (a.name > b.name) { return 1; }
return 0;
});
return newObj;
}
And simply use JSON.parse() and JSON.stringify() to convert JSON to and from objects.
It might help you
var data ={
"sections": [
{
"name": "FooBar",
"rubrics": [{"name": "Foo", "items": [{"id": 10000001,"name": "Lorem"}, {"id": 10000002,"name": "Stet"}, {"id": 10000003,"name": "Ipsum"}]
}, {
"name": "Bar",
"items": [{
"id": 10000004,
"name": "Name"
}, {
"id": 10000005,
"name": "Lorum"
}, {
"id": 10000006,
"name": "Boah"
}]
}]
}, {
"name": "BlahBloob",
"rubrics": [{
"name": "Bla",
"items": [{
"id": 10000013,
"name": "Gut"
}]
}, {
"name": "Bloob",
"items": [{
"id": 10000014,
"name": "Name"
}, {
"id": 10000015,
"name": "Lorem"
}]
}]
}]
};
var itemObj = {};
var itemArr = [];
var sections = data.sections;
for(var i=0;i<sections.length;i++)
{
for(var j=0;j<sections[i].rubrics.length;j++){
for(var k=0;k<sections[i].rubrics[j].items.length;k++){
var itemObj;
itemObj['id'] = sections[i].rubrics[j].items[k].id;
itemObj['name'] = sections[i].rubrics[j].items[k].name;
itemArr.push(itemObj);
}
}
}
var finalObj = {"items":itemArr};
console.log(finalObj);
JSFiddle
I am trying to convert this array to an object. Using underscore, I want to convert this array :
[
{
"id": "parentA",
"children": [
{
"name": "name1"
},
{
"name": "name2"
},
{
"name": "name3"
}
]
},
{
"id": "parentB",
"children": [
{
"name": "name4"
},
{
"name": "name5"
},
{
"name": "name6"
}
]
}]
into an object that looks like this:
{
"name1": "parentA",
"name2": "parentA",
"name3": "parentA",
"name4": "parentB",
"name5": "parentB",
"name6": "parentB"
}
I'm really just looking for the cleanest/simplest way possible.
Here's a fairly short way to do it with two reduce:
var data = [
{
"id": "parentA",
"children": [
{
"name": "name1"
},
{
"name": "name2"
},
{
"name": "name3"
}
]
},
{
"id": "parentB",
"children": [
{
"name": "name4"
},
{
"name": "name5"
},
{
"name": "name6"
}
]
}];
var out = _.reduce(data, function(result, parent) {
_.reduce(parent.children, function(r, child) {
r[child.name] = parent.id;
return r;
}, result);
return result;
}, {});
document.write(JSON.stringify(out));
<script src="http://underscorejs.org/underscore-min.js"></script>
var a = [{
"id": "parentA",
"children": [{
"name": "name1"
}, {
"name": "name2"
}, {
"name": "name3"
}]
}, {
"id": "parentB",
"children": [{
"name": "name4"
}, {
"name": "name5"
}, {
"name": "name6"
}]
}];
var new_obj = {};
var len = a.length;
for (j = 0; j < len; j++) {
var c = $.extend({}, a[j]);
var children_length = (c.children).length;
for (i = 0; i < children_length; i++) {
var temp = ((a[j].children)[i]).name;
new_obj[temp] = c.id;
}
}
document.write(JSON.stringify(new_obj));
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
You'll only need to use underscore if you're supporting browsers without native reduce and forEach array methods, but you can do it like this.
var result = _.reduce(array, function(memo, entry) {
_.each(entry.children, function(child) {
memo[child.name] = entry.id;
});
return memo;
}, {});
function expand(list){
return _.reduce(list,function(a,b) {
_.each(b.children, function(c) {
a[c.name] = b.id;
});
return a;
},{});
}
Check the output for your sample here