Suppose I have this array of object:

let arr = 
[
   { id: "1"},
   { id: "2"},
   { id: "3"}
]

I would create a list of arrays, so I tried:

arr.map(x => x.id);

but this will return:

["1", "2", "3"]

I want an array for each value, eg: ["1"] ["2"] ["3"]

Suppose I have this array of object:

let arr = 
[
   { id: "1"},
   { id: "2"},
   { id: "3"}
]

I would create a list of arrays, so I tried:

arr.map(x => x.id);

but this will return:

["1", "2", "3"]

I want an array for each value, eg: ["1"] ["2"] ["3"]

• javascript

• So return an array? – SLaks Commented Feb 15, 2019 at 18:18
• Are you after an array of small arrays then? What you show that you want isn't a single entity. – lurker Commented Feb 15, 2019 at 18:18
• @lurker the expected result is three array, each array have a value – sfarzoso Commented Feb 15, 2019 at 18:19
• .map isn't going to create three independent arrays ["1"] ["2"] ["3"]. It can, however, create an array of arrays, [["1"], ["2"], ["3"]]. If you want them individually, you probably want to do something with arr.forEach(...)? – lurker Commented Feb 15, 2019 at 18:24

3 Answers 3

If you want an array of each then do

arr.map(x=>[x.id]);

try this

arr.map(x => [x.id]);

Note that if you want to get an array with all the object values, you can use Object.values(). This will work for object with one key and for objects with multiple keys.

let arr = 
[
   {id: "1", foo:"bar"},
   {id: "2"},
   {id: "3"}
];

console.log(arr.map(x => Object.values(x)));

Other useful cases could be:

1) Get an array with the keys for each object => Object.keys()

let arr = 
[
   {id: "1", foo:"bar"},
   {id: "2"},
   {id: "3"}
];

console.log(arr.map(x => Object.keys(x)));

2) Get an array with the pairs of [key, value] (entries) for each object => Object.entries()

let arr = 
[
   {id: "1", foo:"bar"},
   {id: "2"},
   {id: "3"}
];

console.log(arr.map(x => Object.entries(x)));