Filtering array so it would remove all undefined objects

Question

I need to filter an array so it would remove undefined objects from it.

I tried with lodash _.filter but didn't succeed (returned completely empty array)

_.filter(myArray, _.isEmpty)

I'm using Angular 6 so anything with typescript or lodash would be perfect.

score 2 · Accepted Answer · answered Nov 12 '18 at 09:04

2

An easier way:

_.filter(myArray, Boolean)

This rids the array of nulls, 0's and undefined's.

answered Nov 12 '18 at 09:04

rrd

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Thanks a lot, since this is the cleanest way I will accept this answer once I can. – raouaoul Nov 12 '18 at 09:08

score 2 · Answer 2 · answered Nov 12 '18 at 09:05

2

Using Javascript also feasible. it supports null,undefined, 0, empty.

newArray = myArray.filter(item=> item);

answered Nov 12 '18 at 09:05

Suresh Kumar Ariya

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score 1 · Answer 3 · edited Nov 12 '18 at 09:04

1

The more simple way

_.filter(myArray, function(o) { return o !== undefined });

edited Nov 12 '18 at 09:04

Ayush Gupta

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answered Nov 12 '18 at 09:03

firegloves

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score 1 · Answer 4 · answered Nov 12 '18 at 09:08

1

You don't need a library; the Javascript array type has a filter method:

var filteredArray = myArray.filter(item => item !== undefined);

answered Nov 12 '18 at 09:08

stone

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ishani shah · Answer 5 · 2018-11-12T11:04:03.823

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var newArray = array.filter(arrayItem => arrayItem)

It will Filtering array so it would remove all undefined objects and assign to new variable called newArray

edited Nov 12 '18 at 11:04

answered Nov 12 '18 at 09:16

ishani shah

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While this might answer the authors question, it lacks some explaining words and/or links to documentation. Raw code snippets are not very helpful without some phrases around them. You may also find [how to write a good answer](https://stackoverflow.com/help/how-to-answer) very helpful. Please edit your answer - [From Review](https://stackoverflow.com/review/low-quality-posts/21387784) – Nick Nov 12 '18 at 10:25

Koushik Chatterjee · Answer 6 · 2018-11-12T09:39:29.780

In filter function of lodash if the callback (you passed as argument) return truthy value that element considered to be retained in resultant array otherwise (in case return falsy) it will not retain that element. Your isEmpty return true if it is Empty and thus the result retains those values (null, undefined, 0, ...). So you can either use

_.filter(myArray, _.negate(_.IsEmpty)) or _.filter(myArray, v => !_.IsEmpty(v))

In the way you are trying

Or, you can directly use _.filter(myArray) but in this case it will not remove empty object or empty array as same like _.filter(myArray, Boolean), passing Boolean is not necessery in case of using lodash

in case you don't want to negate and want a simpler solution for removing all the empty element, then you can use

_.reject(myArray, _.isEmpty)

Filtering array so it would remove all undefined objects

6 Answers6