How to retrieve property from an array of object and those in a seperate object using javascript?

Question

i want to retrieve certain properties from the array of object and store it in a array.

the data structure looks like below,

object_arr [{…}]0: first_property: "color" id: 25 x: 10 y: 50 z: 56 _proto__: Objectlength: 1__proto__: Array(0)

i want to retrieve x, y and z values so the output should be like below

(3) [10, 50, 56] 0: 10 1: 50 2: 56 length: 3 __proto__: Array(0) so final_output[0] should give me 10, final_output[1] should give me 50 and final_output[2] should give 56

what i have tried?

let final_output = object_arr.map(m => { return [ m.x, m.y, m.z ] });

the final_output looks like this,

final_output [Array(3)] 0: (3) [10, 50, 56] length: 1 the expected output is as below, final_output (3) [10, 50, 56] 0: 10 1: 50 2: 56 length: 3

how can i fix this. could someone help me with this. thanks.

i have updated the question what final output looks like with the code that i had tried. — someuser2491
– someuser2491, Commented Nov 5, 2019 at 13:15
@someuser2491 can you show the expected output when you have multiple objects in your input array (instead of just one)? — Nick Parsons
– Nick Parsons, Commented Nov 5, 2019 at 13:16
I'll just answer the literal question, although i am quite confused about this one: finalOutput = (({x, y, z}) => [x, y, z])(object_arr[0]). — ASDFGerte
– ASDFGerte, Commented Nov 5, 2019 at 13:20

Elisha Senoo · Accepted Answer · 2019-11-05 13:26:53Z

1

Do this:

let object_arr = { first_property: "color", id: 25, x: 10, y: 50, z: 56} let final_output = [object_arr.x, object_arr.y, object_arr.z];

edited Nov 5, 2019 at 13:26

answered Nov 5, 2019 at 13:22

Elisha Senoo

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2 Comments

someuser2491 Over a year ago

thanks this should work. can this be done in single statement.

Scott Sauyet Over a year ago

I don't think that's the input format. There's an array wrapped around it.

Scott Sauyet · Accepted Answer · 2019-11-05 13:27:14Z

This is quite simple. I think your confusion is stemming from trying to work with the input array as a whole. If you only want the data from its first element, you don't need map. Just address it directly with [0]:

let object_arr = [{ first_property: "color", id: 25, x: 10, y: 50, z: 56}] let final_output = [object_arr [0] .x, object_arr [0] .z, object_arr [0] .z]; console .log (final_output)

Nick Parsons · Accepted Answer · 2019-11-05 13:53:20Z

If your array only contains the one object, you can add its properties directly into an array like so:

const object_arr = [{first_property:"color",id:25,x:10,y:50,z:56}]; const [{x, y, z}] = object_arr; // use destructuring to get the object keys from the array const res = [x, y, z]; // create an array containing x, y, z properties console.log(res);

If your array can contain multiple objects, you could use .flatMap() by mapping your properties to an array, which will then fall into a larger resulting array. This way, all x, y and z properties (of all objects) will be mapped to one larger output array:

const object_arr = [{first_property:"color",id:25,x:10,y:50,z:56}]; const res = object_arr.flatMap(o => [o.x, o.y, o.z]); console.log(res);

The flatMap version would be odd in the case where there is more than one element in the input array. It's possibly what would be wanted, with a sequence of x, y, and z values, but that seems unlikely.
@ScottSauyet I agree. I originally thought it seemed odd and would've imagined that the solution provided earlier today was enough to fulfil OPs needs. However, it seems as though it wasn't what the OP was after, so I assumed they wanted a flatMap if they're using an array. Overall both questions aren't very clear in my eyes, and so I gave my best estimate at what the OP was after (hence the 2 solutions)

Saima Haji · Accepted Answer · 2019-11-05 13:18:01Z

You can clearly see : final_output [Array(3)] 0: (3) [10, 50, 56] which is array of array. So to get value 10 you will have to do: final_output[0][0]. Or output=final_output[0]; Then output[0]

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