Javascript - Chrome Console - What does "Array(0)" mean? - Stack Overflow

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I am using Console.log to identify the array values of a function. While examining the console I see a number of places where Array(0) exists:

In particular, I have created an array of key value pairs (see "x" and "testedElements" (same object) at the bottom of the picture above.)

When I expand "x" out that "Array(0)" sits at the top of an array element... I am unsure what "Array(0) means.. does it signify that this element is an array?

I was actually trying to recreate the structure of "full MENU" at the top of the console picture but I have "Array(0)" displaying in the middle of testedElements/x...

I am using Console.log to identify the array values of a function. While examining the console I see a number of places where Array(0) exists:

In particular, I have created an array of key value pairs (see "x" and "testedElements" (same object) at the bottom of the picture above.)

When I expand "x" out that "Array(0)" sits at the top of an array element... I am unsure what "Array(0) means.. does it signify that this element is an array?

I was actually trying to recreate the structure of "full MENU" at the top of the console picture but I have "Array(0)" displaying in the middle of testedElements/x...

• javascript
• arrays
• google-chrome

Share Follow edited Jun 20, 2020 at 9:12 CommunityBot 111 silver badge asked Dec 27, 2017 at 13:11 si2030si2030 4,04588 gold badges4646 silver badges9696 bronze badges 2

• 7 It means an array with zero length. – JJJ Commented Dec 27, 2017 at 13:12
• It is initialized as array but has an object structure. – Miquel Al. Vicens Commented Dec 27, 2017 at 13:14

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1 Answer 1

Sorted by: Reset to default 3

That's how Chrome displays an 0-length array in value summaries in the console. Empty arrays can still contain fields due to the nature of JavaScript.

var obj = {};
obj.array = [];
obj.array.myField = 1;
console.log(obj);

This will log the following in the console:

> {array: Array(0)}

And when I expand it:

{array: Array(0)}
  array: Array(0)
    myField: 1
    length: 0
    __proto__: Array(0)
  __proto__: Object

This shows that named fields are not items in an array.

If you want an associative array (Array with named indexes), you should use plain JavaScript objects.

var obj = {};
obj.A = 10;

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