How to know if an array is Empty?

Question

I'm passing an array from an API and want to know if the array is empty, to print an error message.

Look at different sites and none of them were working.

      {this.props.items ? errorMessage : <h1>Working</h1>}

Possible duplicate of [How can I check whether an array is null / empty?](https://stackoverflow.com/questions/2369967/how-can-i-check-whether-an-array-is-null-empty) — Engineer, Aug 14 '19 at 08:48

score 2 · Answer 1 · answered Aug 14 '19 at 08:45

2

You can use length property

  {this.props.items.length == 0 ? errorMessage : <h1>Working</h1>}

answered Aug 14 '19 at 08:45

Idan

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@Martin hah for you i can replace to "up arrow" – Idan Aug 14 '19 at 09:00

score 1 · Answer 2 · answered Aug 14 '19 at 08:45

1

this.props.items && this.props.items.length > 0 ? <h1>Working</h1> : errorMessage

answered Aug 14 '19 at 08:45

Mukesh Soni

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score 1 · Answer 3 · answered Aug 14 '19 at 08:49

1

Fist check weather Array exists or not then check the length of Array greater than 0, always use double negations to convert that array into bool type

{!!this.props.items && this.props.items.length > 0 ? <h1>Working</h1> : errorMessage}

answered Aug 14 '19 at 08:49

Harsh kurra

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score 1 · Answer 4 · answered Aug 14 '19 at 08:50

1

Check the lodash library. It's very helpful for that kind of needs.

https://lodash.com/docs/4.17.15#isEmpty

With this you could just use:

{isEmpty(this.props.items) ? errorMessage: <h1>Working</h1>}

answered Aug 14 '19 at 08:50

pawelbylina

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score 0 · Accepted Answer · answered Aug 14 '19 at 08:54

0

Safer to check with the type before checking its length, as type string can return length as well

{ Array.isArray(this.props.items) && this.props.items.length < 1 ? errorMessage : <h1>Working</h1> }

answered Aug 14 '19 at 08:54

Jee Mok

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How to know if an array is Empty?

5 Answers5