Javascript remove null from object

Question

I'm having afunction that is merging two arrays like this:

var sorting = data.genre.map((i) => data_info.find((o) => o.id === i));

The problem in this function is if it couldn't find genre in data_info it adds null to the object arra and therefore my function fails.
So the question is: How could I remove in above single line all values that are null?

I get this output from thr line above:

[{"id":1,"category":"Action"},{"id":2,"category":"Adventure"},null]

And need to get this:

[{"id":1,"category":"Action"},{"id":2,"category":"Adventure"}]

I tried to add && data_info(o) !== null to the line above but I get null in the object array anyway.

Add a filter to the output of map. data.genre.map((i) => data_info.find((o) => o.id === i)).filter((i) => return i != null ); — gurvinder372
– gurvinder372, Commented Oct 11, 2017 at 7:52
The map function applies the operation on each item of the array and returns an array with exactly the same number of elements as in the input array. — ajaysinghdav10d
– ajaysinghdav10d, Commented Oct 11, 2017 at 7:54
Possible duplicate of How to remove item from array by value? — Nikola Lukic
– Nikola Lukic, Commented Oct 11, 2017 at 8:13

Karim · Accepted Answer · 2017-12-01 14:14:27Z

2

change .map to .filter

var sorting = data.genre.filter((i) => data_info.find((o) => o.id === i) ? true : false);

edited Dec 1, 2017 at 14:14

answered Oct 11, 2017 at 7:54

Karim

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Paul Fitzgerald · Accepted Answer · 2017-10-11 07:54:13Z

1

You can filter the result of your map function to remove null.

var sorting = data.genre.map((i) => data_info.find((o) => o.id === i)).filter(item => {
   return item !== null;
});

The filter() method creates a new array with all elements that pass the test implemented by the provided function.

answered Oct 11, 2017 at 7:54

Paul Fitzgerald

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Mihai Alexandru-Ionut · Accepted Answer · 2017-10-11 07:59:25Z

1

You can use filter method by passing a callback provided function.

var sorting = data.genre.map((i) => data_info.find((o) => o.id === i)).filter(function(item){
    return item!=null;
});

edited Oct 11, 2017 at 7:59

answered Oct 11, 2017 at 7:54

Mihai Alexandru-Ionut

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