Map array inside an object

Question

I've the following complex JSON object that has got array and array inside an array. How can parse those arrays and create an object array for each element in the array. I'm using lodash library in my project, just in case if there are any functions available.

   {
  studentId: 123
  name: XYZ
  phone: 34234234
  gender: M
  subjects: [{
     studentId: 123
     subjectName: Math
     scores:50
    assignments:[
     {
        type: Internal,
        submitted: yes,
        status: failed 
     },
     {
        type: External,
        submitted: yes,
        status: passed 
     }] 
},
{
     studentId: 123
     subjectName: Science
     score: 20
     assignments:[
     {
        type: Internal,
        submitted: yes,
        status: passed 
     },
     {
        type: External,
        submitted: yes,
        status: failed 
     }]
}] 

}

Expecting:

[{
  studentId:123,
  name: XYZ
  phone: 34234234
  gender: M,  
  subjectName: Math
  scores:50
  assignments:[
     {
        type: Internal,
        submitted: yes,
        status: failed 
     },
     {
        type: External,
        submitted: yes,
        status: passed 
     }]
},
{
 studentId:123,
  name: XYZ
  phone: 34234234
  gender: M,  
  subjectName: science
  scores:20
  assignments:[
     {
        type: Internal,
        submitted: yes,
        status: failed 
     },
     {
        type: External,
        submitted: yes,
        status: passed 
     }]
}
]

Answer 1

You can use omit to get the details of the student without the subjects array, use these details to transform each item in the subjects array using defaults through map .

var details = _.omit(data, 'subjects');
var result = _.map(data.subjects, function(subject) {
  return _.defaults({}, details, subject);
});

 var data = { studentId: '123', name: 'XYZ', phone: '34234234', gender: 'M', subjects: [{ studentId: '123', subjectName: 'Math', scores: 50, assignments: [{ type: 'Internal', submitted: 'yes', status: 'failed' }, { type: 'External', submitted: 'yes', status: 'passed' } ] }, { studentId: '123', subjectName: 'Science', score: 20, assignments: [{ type: 'Internal', submitted: 'yes', status: 'passed' }, { type: 'External', submitted: 'yes', status: 'failed' } ] } ] }; var details = _.omit(data, 'subjects'); var result = _.map(data.subjects, function(subject) { return _.defaults({}, details, subject); }); console.log(result); 

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Answer 2

I encourage you to use Normalizr package. It's very useful and takes all care about your collections even if they're nested.