Loop through an object and create new array

Question

I have an array of objects, I'm trying to loop through them via map function and create an output as follows:

Desired output

dataSet = [
 [John, Doe, Sales],
 [Jane, Doe, HR], 
 [Jack, Doe, Manager]
]

My array of objects:

[[object],[object],[object]]

Here is what I have tried so far:

 users.map((item) => {
  dataSet.push(item.profile.firstName, item.profile.role)
 })

However my output:

["John","Jane","Jack"]

How can I push each loop into new array?

Thanks

How are you getting that output? What is the actual input? It looks like there should be 6 items in the output array, since you're pushing 2 items per iteration. — castletheperson
– castletheperson, Commented Apr 22, 2017 at 3:37
As a sort of aside, if you are not using the return value of .map() then you're using .map() incorrectly and should be using .forEach() instead. — nnnnnn
– nnnnnn, Commented Apr 22, 2017 at 3:41
is your array of objects an array of arrays containing objects? [[{...}],[{...}]], or an array of objects [{...},{...}] — synthet1c
– synthet1c, Commented Apr 22, 2017 at 3:42

Junbang Huang · Accepted Answer · 2017-04-22 03:42:30Z

2

Actually, you are pretty close. Just make what you want to push an array. Try the following codes:

users.forEach((item) => {
  dataSet.push([item.profile.firstName, item.profile.lastName, item.profile.role]);
});

edited Apr 22, 2017 at 3:42

answered Apr 22, 2017 at 3:35

Junbang Huang

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1 Comment

Junbang Huang Over a year ago

@4castle you dare absolutely correct. I've updated it

castletheperson · Accepted Answer · 2017-04-22 03:42:24Z

1

Assuming your original data looks like:

data: [
    ...
    {
        profile: {
            firstname: "John",
            lastname: "Doe",
            role: "Sales"
        }
    },
    ...
];

You could do this:

var dataSet = data.map((person) => {
    let profile = person.profile;
    return [
        profile.firstname,
        profile.lastname,
        profile.role
    ];
});

Hope this helps!

edited Apr 22, 2017 at 3:42

castletheperson

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answered Apr 22, 2017 at 3:39

Kyle Richardson

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Comments

synthet1c · Accepted Answer · 2017-04-22 03:45:17Z

1

When you are mapping the array of objects you should just return an array with the values you want.

const john = { firstName: 'John', lastName: 'Doe', role: 'Sales' }
const jane = { firstName: 'Jane', lastName: 'Doe', role: 'HR' }
const jack = { firstName: 'Jack', lastName: 'Doe', role: 'Manager' }
const users = [ john, jane, jack ]
const dataSet = users.map(user => ([ user.firstName, user.lastName, user.role ]))
console.log(dataSet)

edited Apr 22, 2017 at 3:45

answered Apr 22, 2017 at 3:35

synthet1c

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Comments

RobG · Accepted Answer · 2017-04-22 04:21:52Z

0

You can do this in a more generic way by allowing for any number of properties on the object using map, e.g.

dataset = [
           {firstName: 'John', lastName: 'Doe', role: 'Sales'},
           {firstName: 'Jane', lastName: 'Doe', role: 'HR'},
           {firstName: 'Jack', lastName: 'Doe', role: 'Manager'}
          ];

var result = dataset.map(obj => Object.keys(obj).map(key => obj[key]));

console.log(result)

answered Apr 22, 2017 at 4:21

RobG

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