How to turn object with array into array?

Question

I'm trying to turn the values of an array inside an object to a normal array.

Right now I'm doing something like this in my AJAX success function:

var obj = data
              
console.log(obj)

var array = Object.keys(obj)
 .map(function(key) {
   return obj[key];
 });

console.log(array)

This is what I get in my console:

{jaar: Array(2)}
 jaar: Array(2)
  0: YEAR(Scan): "2020"
   [[Prototype]]: Object
  1: YEAR(Scan): "2021"
   [[Prototype]]: Object
  length: 2
  [[Prototype]]: Array(0)
  [[Prototype]]: Object

I want to have something simply as this

["2020", "2021"]

How can I achieve this and what am I doing wrong right now?

console.log(obj) at the start gives this output in the console:

jaar: Array(2)
0: {YEAR(Scan): '2020'}
1: {YEAR(Scan): '2021'}
length: 2
[[Prototype]]: Array(0)
[[Prototype]]: Object ```

Have you tried Object.values(obj.jaar)? developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/… — Justinas
– Justinas, Commented Oct 12, 2021 at 7:46
Hey @Justinas I've just tried what you've said. It seems to be giving me a correct array, problem now is the values inside are undefined. — Swauters
– Swauters, Commented Oct 12, 2021 at 7:50

Roman Kurbatov · Accepted Answer · 2021-10-12 07:53:48Z

1

If you have a plain object like const obj = { x: 10, y: 20 } and you want to have an array of its values, you can simply use Object.values(obj) that will return you [10, 20].

Seems like your object has more complex structure.

If you know for sure, any value of your object is a value or array, like const obj2 = { x: 10, y: [20, 30, 40], z: [50, 60]} you can flatten it.

Object.values(obj2).flat() will return you [10, 20, 30, 40, 50, 60].

For more complex structures you need to have more complex handlers.

answered Oct 12, 2021 at 7:53

Roman Kurbatov

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Comments

Tushar Shahi · Accepted Answer · 2021-10-12 07:54:09Z

1

jaar is already an array of objects. You can simply use .map() and get the respective property value from each array element.

let ans =jaar.map(x => x['YEAR(Scan)']);

answered Oct 12, 2021 at 7:54

Tushar Shahi

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Comments

fdomn-m · Accepted Answer · 2021-10-12 08:15:59Z

0

Other answer provides the must succinct code (using .map) - to make the the smallest change to your existing code, change:

You can read the YEAR(Scan) property like so:

return obj[key]["YEAR(Scan)"];

Updated code:

var obj = 
  [ 
    { "YEAR(Scan)":"2020" },
    { "YEAR(Scan)":"2021" }
  ]
  

console.log(obj)

var array = Object.keys(obj)
 .map(function(key) {
   return obj[key]["YEAR(Scan)"];
 });

console.log(array)

edited Oct 12, 2021 at 8:15

answered Oct 12, 2021 at 7:57

fdomn-m

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4 Comments

Swauters Over a year ago

I'm still getting undefined when I console.log

Swauters Over a year ago

I don't believe YEAR(Scan) is an actual string value, it's greyed out in the console.

fdomn-m Over a year ago

Hard to tell, I had to recreate the object from the console.log as it wasn't provided. Added the console.log(obj) (and to the snippet above) and it looks the same to me in the browser console 0: {YEAR(Scan): '2020' } - "year(scan)" is greyed and not in quotes. Note, it is not a string, you use ["string"] to access variables with invalid variable names var YEAR(Scan)=2020 would give an error. Perhaps you could add: console.log(JSON.stringify(obj)) so the original obj can be recreated faithfully.

Swauters Over a year ago

{jaar: Array(2)}jaar: (2) [{…}, {…}][[Prototype]]: Object chart.js:567 (2) [{…}, {…}]

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