CODEWITHSUNDEEP
javascript
someuser2491
someuser2491

Reputation: 1968

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

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.

Upvotes: 0

Views: 54

Answers (4)

Nick Parsons
Nick Parsons

Reputation: 50759

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);

Upvotes: 0

Scott Sauyet
Scott Sauyet

Reputation: 50797

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)

Upvotes: 1

Elisha Senoo
Elisha Senoo

Reputation: 3594

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];

Upvotes: 1

Saima Haji
Saima Haji

Reputation: 175

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]

Upvotes: 0

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