NODE.JS Multidimensional/Sub array PUSH prototype

Question

I am attempting to sort data into an appropriate category of array once parsed;

First lets initialize my Array like so.

const foo = {
    bar: {},
    bar2: {}
}

I am unable to utilize the .push prototype on the subarray build, for example.

foo.bar.push('foobar');

The error I will receive is

TypeError: Cannot read property 'push' of undefined

The array has been initialized using the first block of code.

I have also attempted to use the following and receive the same response from the console.

foo[0].push('foobar');

How could one push data to a subarray?

BONUS POINTS/PS. What is this kind of array called? Is this a subarray or multidimensional array or neither?

Thanks in advance.

What is this kind of array called? which kind? {} is an Object — arizafar
– arizafar, Commented Oct 15, 2019 at 9:16
@RenéDatenschutz no it's not, it's without the constructor call. — arizafar
– arizafar, Commented Oct 15, 2019 at 9:18
@AZ_ it's with the constructor, without is sugar w3schools.com/js/js_arrays.asp — Scriptkiddy1337
– Scriptkiddy1337, Commented Oct 15, 2019 at 9:27

shubham-gupta · Accepted Answer · 2019-10-15 09:12:30Z

2

What you are declaring is an object not array.

const foo = {
    bar: {},
    bar2: {}
}

In this case bar and bar2 both are objects and not array. And push is not available on object's prototype.

Use this to declare arrays inside object.

const foo = {
    bar: [],
    bar2: []
}

answered Oct 15, 2019 at 9:12

shubham-gupta

2081 silver badge5 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Christopher Allen Over a year ago

You saved the day! and bonus points as well! This is an OBJECT not array

shubham-gupta Over a year ago

Glad I could help.

devamat · Accepted Answer · 2019-10-15 09:16:32Z

0

I would add to shubham-gupta response that if you want to push to foo you should declare it as an array as well:

const foo = [{
    bar: [],
    bar2: []
}]

answered Oct 15, 2019 at 9:16

devamat

2,5139 gold badges33 silver badges57 bronze badges

2 Comments

arizafar Over a year ago

then you can't do foo.bar.push('foobar');

devamat Over a year ago

Correct, you should use foo[0].bar.push('poteto')

Harshith Rai · Accepted Answer · 2019-10-15 09:25:33Z

0

Christopher, the error says what it says because, it is not possible to push an element into an object, but only an array.

Check this page out, which differentiate the two.

To set the value of a key inside an object you do: <your_object>.<your_key>= <your_value>;

To push an element into an array, you do: <your_array>.push(<your_element>);

Hence the bar elements inside foo should be arrays => [], not objects;

In your case here, you seem to be wanting to push the element "foobar" into the array bar inside of the object foo.

To do that, all you need to do is:

const foo = {
    bar: [],
    bar2: []
}
foo.bar.push('foobar');

answered Oct 15, 2019 at 9:25

Harshith Rai

3,1067 gold badges25 silver badges37 bronze badges

Collectives™ on Stack Overflow

NODE.JS Multidimensional/Sub array PUSH prototype

3 Answers 3

2 Comments

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

2 Comments

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related