Error in Javascript chrome when trying to determine the length of an array

Question

Error in Javascript chrome when trying to determine the length of an array

I am facing an unusual issue with the JavaScript console in Chrome. When I type the following code into the console:

var numbers = new Array(["/php/.svn/tmp", "/php/.svn/props"]);

it returns "undefined." This leads me to believe that 'numbers' is an array with 2 elements. However, when I enter:

numbers

it displays:

[Array[2]]

Then, when I check the length using:

numbers.length

it returns 1...but why? Shouldn't it be 2? Where am I going wrong here? Is there a method that can return 2? Thank you in advance.

EDIT: Let me elaborate on my issue further. I have a function that returns this when two items are selected:

myFolders.getSelected()
["/php/.svn", "/php/upload.php"]

and this when only one item is selected:

myFolders.getSelected()
"/php/upload.php"

As you can see, the second one is not an array. Now, I am using this method to trigger a calculation of a global variable when the selected item changes:

function calculateNumberOfElements(){
    var numbers = new Array(myFolders.getSelected());
    selectedElementCount = numbers[0].length;
}

However, it always returns 1 or the number of characters when only one item is selected.

javascript google-chrome

Answer 1

Answer №1

When you create an array inside another array, it will return 1.

console.log( num[0].length ); // 2

In order to fix this, it should be:

var num = ["/php/.svn/tmp", "/php/.svn/props"];

or

var num = new Array("/php/.svn/tmp", "/php/.svn/props"); // without `[` and `]`

After making these changes, use console.log( num.length );

Answer 2

When you create an array inside another array, it will return 1.

console.log( num[0].length ); // 2

In order to fix this, it should be:

var num = ["/php/.svn/tmp", "/php/.svn/props"];

or

var num = new Array("/php/.svn/tmp", "/php/.svn/props"); // without `[` and `]`

After making these changes, use console.log( num.length );

Answer 3

Answer №2

Avoid using New Array, opt for literal notation instead:

var numero = ["/php/.svn/tmp", "/php/.svn/props"];

Update (In response to your feedback)

If you have a function called myFolders.getSelected() that returns a single string and you wish to add it to an array, you can do so declaratively:

var numero = [myFolders.getSelected()]

Alternatively, if you intend to add multiple values, such as in a loop, you can push a new value into the array:

var numero = [];
...
numero.push(myFolders.getSelected());

Answer 4

Avoid using New Array, opt for literal notation instead:

var numero = ["/php/.svn/tmp", "/php/.svn/props"];

Update (In response to your feedback)

If you have a function called myFolders.getSelected() that returns a single string and you wish to add it to an array, you can do so declaratively:

var numero = [myFolders.getSelected()]

Alternatively, if you intend to add multiple values, such as in a loop, you can push a new value into the array:

var numero = [];
...
numero.push(myFolders.getSelected());

Answer 5

Answer №3

["/php/.svn/tmp", "/php/.svn/props"]

will result in an array that contains these two strings.

new Array(arg0, arg1 ... argn); creates an array with elements specified as arguments.

new Array(["/php/.svn/tmp", "/php/.svn/props"]);

generates an array where the first element is an array of two strings.

Try using numero[0].length to see what you obtain.

Alternatively, you can define your array like this:

var numero = ["/php/.svn/tmp", "/php/.svn/props"];

Answer 6

["/php/.svn/tmp", "/php/.svn/props"]

will result in an array that contains these two strings.

new Array(arg0, arg1 ... argn); creates an array with elements specified as arguments.

new Array(["/php/.svn/tmp", "/php/.svn/props"]);

generates an array where the first element is an array of two strings.

Try using numero[0].length to see what you obtain.

Alternatively, you can define your array like this:

var numero = ["/php/.svn/tmp", "/php/.svn/props"];

Error in Javascript chrome when trying to determine the length of an array

Answer №1

Answer №2

Answer №3

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