How to convert array object to single array?

Question

I have an object array. I need to convert it single array without key.

I need array like this:

["test","test"]

I also need to remove that value if I got undefined instead of other value.

My code:

const list = [
    {
        "type": "undefined"
    },
    {
        "type": "test"
    },
    {
        "type": "test"
    }
]

var findAndValue = list.map(Object.values);
console.log(findAndValue);

`list.map(({ type }) => type).filter(v => v !== "undefined")` — 0stone0, Nov 04 '22 at 15:14
Does this answer your question? [How can I remove a specific item from an array?](https://stackoverflow.com/questions/5767325/how-can-i-remove-a-specific-item-from-an-array) — 0stone0, Nov 04 '22 at 15:17
Are you sure you want to test for undefined given as string value? — Ibrahim Sharaf, Nov 04 '22 at 15:21
@RohitVerma Did you get a chance to look into the answer I added ? I hope it will work as per your expectation. — Debug Diva, Nov 06 '22 at 16:59

score 1 · Accepted Answer · answered Nov 04 '22 at 15:16

If you just want the value from one property, only return that property value from the map operation:

const list = [
  { "type": "undefined" },
  { "type": "test" },
  { "type": "test" }
];
const result = list.map(x => x.type);
console.log(result);

To filter out the "undefined" string, use filter:

const list = [
  { "type": "undefined" },
  { "type": "test" },
  { "type": "test" }
];
const result = list.map(x => x.type).filter(x => x !== "undefined");
console.log(result);

score 1 · Answer 2 · answered Nov 04 '22 at 15:18

1

2 steps:

First extract all the values into a list

Second, remove any values you dont want

const values = list.map(({ type }) => type)
cosnt filteredValues = values.filter(val => val !== undefined)

answered Nov 04 '22 at 15:18

Wizard

462
1
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14

score 1 · Answer 3 · answered Nov 05 '22 at 16:04

Are you sure undefined is a string type ? Ideally it should be just undefined and we can filter that out by using Boolean along with filter method.

Live Demo :

const list = [
  { "type": undefined },
  { "type": "test" },
  { "type": "test" }
];
const res = list.map(({ type }) => type).filter(Boolean);

console.log(res);

How to convert array object to single array?

3 Answers3