Is a JavaScript array index a string or an integer?

Question

I had a generic question about JavaScript arrays. Are array indices in JavaScript internally handled as strings?

I read somewhere that because arrays are objects in JavaScript, the index is actually a string. I am a bit confused about this, and would be glad for any explanation.

Answer

That is correct so:

> var a = ['a','b','c']
undefined
> a
[ 'a', 'b', 'c' ]
> a[0]
'a'
> a['0']
'a'
> a['4'] = 'e'
'e'
> a[3] = 'd'
'd'
> a
[ 'a', 'b', 'c', 'd', 'e' ]

Accepted Answer

That is correct so:> var a = ['a','b','c']undefined> a[ 'a', 'b', 'c' ]> a[0]'a'> a['0']'a'> a['4'] = 'e''e'> a[3] = 'd''d'> a[ 'a', 'b', 'c', 'd', 'e' ]

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Answer