Join nested array

Question

I have a result from Q.all() which is something like this -

promise = [Arr1,Arr2,Arr3....]

Each Arr can be either null or an array of plain JS objects.

I want to join all these arrays to one big array;

I can loop over and use array concat method to join them.

Is there any other elegant solution which is inbuilt in JS ?

Here is sample array -

    [
      {
        "endDate": "2015-06-11 14:52:00",
        "quantity": 75,
      },
      {
        "endDate": "2015-06-11 14:42:00",
        "quantity": 78,
      },
      {
        "endDate": "2015-06-01 14:43:00",
        "quantity": 69,
      },
      {
        "endDate": "2015-05-14 13:38:00",
        "quantity": 85,
      }
    ]

I have these libraries available as well lodash, angular

Your sample is just one array, but your question says you have an array of them (e.g., nested arrays). — T.J. Crowder
– T.J. Crowder, Commented Jun 12, 2015 at 6:54
@T.J.Crowder yes its sample of one array. All the other array follow same structure — Sushant
– Sushant, Commented Jun 12, 2015 at 6:55
If you have a simple loop that does what you want, I would stick with it. I bet it will be more readable than the LoDash solutions that have been proposed. — Michael Geary
– Michael Geary, Commented Jun 12, 2015 at 6:56

T.J. Crowder · Accepted Answer · 2015-06-12 06:57:47Z

3

I believe that would be a combination of flattenDeep (to do the flattening) and without (to remove nulls — at least, I think you wanted to remove nulls; if not, take without out):

var result = _.without(_.flattenDeep(yourArray), null);

Live Example:

// NOTE: You said you had an array with arrays in it, so I've taken
// the one array you gave and used it as two entries in the array
// below (with some minor mods). Note also the nulls.
var yourArrays = [
    [
        {
            "endDate": "2015-06-11 14:52:00",
            "quantity": 75
        },
        {
            "endDate": "2015-06-11 14:42:00",
            "quantity": 78
        },
        {
            "endDate": "2015-06-01 14:43:00",
            "quantity": 69
        },
        {
            "endDate": "2015-05-14 13:38:00",
            "quantity": 85
        }
    ],
    null,
    null,
    [
        {
            "endDate": "2015-07-11 14:52:00",
            "quantity": 12
        },
        {
            "endDate": "2015-07-11 17:42:00",
            "quantity": 34
        },
        {
            "endDate": "2015-07-01 13:43:00",
            "quantity": 56
        },
        {
            "endDate": "2015-08-14 12:38:00",
            "quantity": 85
        }
    ]
];
var result = _.without(_.flattenDeep(yourArrays), null);
document.body.insertAdjacentHTML(
"beforeend",
"<pre>" + JSON.stringify(result, null, 2) + "</pre>"
);

<script src="https://cdn.rawgit.com/lodash/lodash/3.0.1/lodash.min.js"></script>

edited Jun 12, 2015 at 6:57

answered Jun 12, 2015 at 6:49

T.J. Crowder

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3 Comments

Adam Boduch Over a year ago

I prefer compact() over without() for removing falsey values.

T.J. Crowder Over a year ago

@AdamBoduch: I don't know he wants to remove all falsey values. :-) Actually, I'm not quite sure where I got the idea he wanted to remove nulls, but I'm fairly sure he does...

Sushant Over a year ago

@T.J.Crowder, Yes I actually wanted to remove nulls thats why I mentioned there are possible null values as well. But without me explicitly mentioning you used without().Great

ozil · Accepted Answer · 2015-06-12 06:54:14Z

0

you cam simple use .map function.

var promise = [[0,1],[2,3],[],[6,7]]
var combineArr = promise.map(function(value, index, array) {
    return array[index];
  });
alert(combineArr);

DEMO

answered Jun 12, 2015 at 6:54

ozil

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