Check if array is empty or null

Question

I would like to know how to check if an array is empty or null in jQuery  I tried array length     0 but it didn t work  It did not throw any error either   This is the code   var album text   new Array        input name  album text       each function      if    this  val    amp  amp     this  val                album text push   this  val             if  album text length     0          error message   html  Error       else        send data

User · Accepted Answer

As long as your selector is actually working, I see nothing wrong with your code that checks the length of the array. That should do what you want. There are a lot of ways to clean up your code to be simpler and more readable. Here's a cleaned up version with notes about what I cleaned up.

var album_text = [];

$("input[name='album_text[]']").each(function() {
    var value = $(this).val();
    if (value) {
        album_text.push(value);
    }
});
if (album_text.length === 0) {
    $('#error_message').html("Error");
}

else {
  //send data
}

Some notes on what you were doing and what I changed.

$(this) is always a valid jQuery object so there's no reason to ever check if ($(this)). It may not have any DOM objects inside it, but you can check that with $(this).length if you need to, but that is not necessary here because the .each() loop wouldn't run if there were no items so $(this) inside your .each() loop will always be something.
It's inefficient to use $(this) multiple times in the same function. Much better to get it once into a local variable and then use it from that local variable.
It's recommended to initialize arrays with [] rather than new Array().
if (value) when value is expected to be a string will both protect from value == null, value == undefined and value == "" so you don't have to do if (value && (value != "")). You can just do: if (value) to check for all three empty conditions.
if (album_text.length === 0) will tell you if the array is empty as long as it is a valid, initialized array (which it is here).

What are you trying to do with this selector $("input[name='album_text[]']")?

User · Answer

User JQuery is EmptyObject to check whether array is contains elements or not   var testArray  1 2 3 4 5   var testArray1     console log jQuery isEmptyObject testArray      false console log jQuery isEmptyObject testArray1      true

User · Answer

I think it is dangerous to use   isEmptyObject from jquery to check whether the array is empty  as  jesenko mentioned  I just met that problem   In the isEmptyObject doc  it mentions      The argument should always be a plain JavaScript Object   which you can determine by   isPlainObject  The return of   isPlainObject     is false

User · Answer

You should check for     empty string  before pushing into your array  Your array has elements that are empty strings  Then your album text length     0 will work just fine

[jquery] Check if array is empty or null

Examples related to jquery

Examples related to arrays

Examples related to is-empty