I console.log(arr) it shows [] but I console.log(arr.length) it shows 0? It's confusing for me, so what is the best way to check if an array contain something?

I console.log(arr) it shows [] but I console.log(arr.length) it shows 0? It's confusing for me, so what is the best way to check if an array contain something?

• javascript
• jquery
• arrays

Share Improve this question Follow edited Jul 13, 2015 at 5:57 Mike Laren 8,1981717 gold badges5252 silver badges7171 bronze badges asked Jul 11, 2015 at 4:05 Lee shienlongLee shienlong 6711 gold badge22 silver badges66 bronze badges 5

• arr.length is the best way to check the length of an array – Jaromanda X Commented Jul 11, 2015 at 4:06
• 3 [] is an empty array, and therefor its length is 0 – what is confusing about that? – C3roe Commented Jul 11, 2015 at 4:06
• Iit is pletely correct ... Javascript arrays are is zero based indexed – leo.fcx Commented Jul 11, 2015 at 4:07
• @CBroe how to check if it's not empty or empty then? – Lee shienlong Commented Jul 11, 2015 at 4:08
• if (arr.length === 0) { /* array is empty */ } – nnnnnn Commented Jul 11, 2015 at 4:08

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2 Answers 2

Sorted by: Reset to default 4

You can check if an array is empty by checking the length property:

if (arr.length === 0) {
    // arr is empty
}

Or, to check if it contains some items:

if (arr.length) {
    // arr is not empty
}

console.log(arr) will show [] for an empty array. That's just how it shows that and a length property of 0 means that there are no items in the array.

This is an array: ['1','2','3','4'], so if the array is empty it will look like this: []. I would do like this:

if(arr && arr.length){ console.log('then the array is created and it has value'); }