How to convert nested array pairs to objects in an array

Question

I have been tasked to convert the following array to an array of object pairs:

var arr = [
  [
    ['firstName', 'Joe'],
    ['lastName', 'Blow'],
    ['age', 42],
    ['role', 'clerk'],
    [
      ['firstName', 'Mary'],
      ['lastName', 'Jenkins'],
      ['age', 36],
      ['role', 'manager']
    ]
  ]
]

I need to transform arr into an array of objects that looks like this:

[
 {firstName: 'Joe', lastName: 'Blow', age: 42, role: 'clerk'},
 {firstName: 'Mary', lastName: 'Jenkins', age: 36, role: 'manager'}
]

Please put what effort you have taken and what output you want — pareshm
– pareshm, Commented Nov 11, 2016 at 7:08
You want like this - var arr = [{'firstName':'Joe','lastName':'Blow','age':42,'role':'clert'},{'firstName':'Mary','lastName':'Jenkins','age':36,'role':'manager'}] — Chetan
– Chetan, Commented Nov 11, 2016 at 7:09
Mention what you have tried, what's the output desired. Also, format the question, add code blocks. The arr is missing a ']' — aliasav
– aliasav, Commented Nov 11, 2016 at 7:11

Edorka · Accepted Answer · 2016-11-11 07:22:33Z

3

Programmatic solution (available too at https://jsfiddle.net/edorka/jnLxyzhb/):

var arr = [[ ['firstName', 'Joe'], ['lastName', 'Blow'], ['age', 42], ['role', 'clerk']], [['firstName', 'Mary'], ['lastName', 'Jenkins'], ['age', 36], ['role', 'manager'] ]];

var empty = {};
var result = arr.map(function(objectArray){
    var object = this;
    var attribute = objectArray.map(function(attrArray){
        var name = attrArray[0], value = attrArray[1];
        object[name] = value;
        return object;
    }, object);
    return this;
}, empty);

console.log(result);

answered Nov 11, 2016 at 7:22

Edorka

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Comments

Chetan · Accepted Answer · 2016-11-11 07:13:20Z

0

You can convert it like this -

var arr = [
            {'firstName':'Joe','lastName':'Blow','age':42,'role':'clert‌'},
            {'firstName':'Mar‌y','lastName':'Jenki‌ns','age':36,'role':‌'manager'}
          ]

answered Nov 11, 2016 at 7:13

Chetan

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1 Comment

Raphael Morgan Over a year ago

what's the difference between this and what they posted? how does this help them achieve that? this just seems like a reiteration of what they said they wanted, plus some quotes

Chinito · Accepted Answer · 2016-11-11 07:14:57Z

0

example of an array of objects

var arr = [
    {
       'firstName' : 'Joe',
       'lastName' : 'Blow',
       'age' : 42,
       'role' : 'clerk'
    },
    {
       'firstName' : 'Mary',
       'lastName' : 'Jenkins',
       'age' : 36,
       'role' : 'manager'
    } 
];

answered Nov 11, 2016 at 7:14

Chinito

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Comments

Nina Scholz · Accepted Answer · 2016-11-11 07:35:23Z

0

You could use an iterative and recursive approach for the nested arrays.

var array = [[['firstName', 'Joe'], ['lastName', 'Blow'], ['age', 42], ['role', 'clerk'], [['firstName', 'Mary'], ['lastName', 'Jenkins'], ['age', 36], ['role', 'manager']]]],
    result = [];

array[0].forEach(function iter(a, i) {
    i || result.push({});
    if (i < 4) {
        result[result.length - 1][a[0]] = a[1];
        return;
    }
    Array.isArray(a) && a.forEach(iter);
});
   
console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

answered Nov 11, 2016 at 7:35

Nina Scholz

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5 Comments

Edorka Over a year ago

Didn't knew about embedded snippets, thanks for your response. However IMHO I see your solution limited by the number of attributes (four) but that would lack elasticity, I mean, if i == 2 then it's a name/value tuple.

Nina Scholz Over a year ago

i used the data i have, and it looks like the first four elements are meant to be part of the object.

Michael Diodoro Over a year ago

That's what I was able to come up with

Michael Diodoro Over a year ago

It does work but I don't think it is the most efficient solution.

Nina Scholz Over a year ago

if you supply more data, than above, i could optimize the proposal.

Cristian Cristea · Accepted Answer · 2016-11-11 08:24:24Z

0

function convert(array) {
  return array.map(function(person) {
    return person.reduce(function(obj, prop, index) {
      if (!obj[prop[0]]) {
        obj[prop[0]] = prop[1];
      }

      return obj;
    }, {});
  }); 
}

use the map function to select each "person" array
use the reduce function to convert each "person" array to an object
the map function will also return a new array of objects
the original array will not be altered

answered Nov 11, 2016 at 8:24

Cristian Cristea

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Comments

Aman Rawat · Accepted Answer · 2016-11-11 07:11:40Z

-1

If you format you your code you will see at first there is 1 closing brace ']' at the end is missing. And you structure is like this

var arr = [
    [
        ['firstName', 'Joe'],
        ['lastName', 'Blow'],
        ['age', 42],
        ['role', 'clerk'],
        [
            ['firstName', 'Mary'],
            ['lastName', 'Jenkins'],
            ['age', 36],
            ['role', 'manager']
        ]
    ]
]

I think you want to do something like this

var arr = [
    [
        ['firstName', 'Joe'],
        ['lastName', 'Blow'],
        ['age', 42],
        ['role', 'clerk']
    ],
    [
        ['firstName', 'Mary'],
        ['lastName', 'Jenkins'],
        ['age', 36],
        ['role', 'manager']
    ]
];

But i will suggest you to do like this

var arr = [
    {
        'firstName': 'Joe',
        'lastName': 'Blow',
        'age': 42,
        'role': 'clerk'
    },
    {
        'firstName': 'Mary',
        'lastName': 'Jenkins',
        'age': 36,
        'role': 'manager'
    }
];

answered Nov 11, 2016 at 7:11

Aman Rawat

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1 Comment

Aman Rawat Over a year ago

Please drop the comment with that negative vote. So i can get where i was wrong

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