How to Determine if an Array Exists or Is Empty in JavaScript?

Checking If an Array is Empty or Exists

In JavaScript, verifying if an array is populated or present is crucial for various operations. Let's explore a situation and its corresponding solution related to array existence and content verification.

Situation:

You need to check if an array called image_array exists or contains any elements to display an image upon the page's initial load. If the array is empty or doesn't exist, you want to disable navigation buttons, display an alert, and create an empty image_array.

Initial Code:

<br>if(image_array.length > 0)</p>
<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false">// Append image to the DOM

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else {

// Disable buttons, alert, and create an empty array

}

Problem:

Your code relies on the existence of the image_array variable. However, the else block unconditionally runs, overriding the existing image_array if it existed, leading to incorrect behavior and preventing the alert from appearing.

Solution:

To properly handle this situation, you can employ the following code:

<br>if (typeof image_array !== 'undefined' && image_array.length > 0) {</p>
<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false">// Array is defined and not empty
// Append image to the DOM

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