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() &&  $(this).val() != '') {
    album_text.push($(this).val());
  }
});
if (album_text.length === 0) {
  $('#error_message').html("Error");
}

else {
  // send data
}

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

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  amp  amp   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

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

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