wp_enqueue_script doesn't load JS in plugin

Question

I wrote the following code in a standalone plugin, but it doesn't work
Please guide me how to modify the code, so the JS file is loaded.

<?php
/*
Plugin Name: Copy post
*/
class CopyPostApi{
    public  function __construct(){
        // Add assets
        add_action( 'wp_enqueue_scripts', array($this, 'load_assets'));
    }
    public function load_assets()
    {
        wp_enqueue_script(
            'main_js',
            plugin_dir_url(__FILE__) . 'assets/main.js',
            array(),
            1,
            true
        );
    } 
}
new CopyPostApi;

Note: I searched and used the suggested codes, but it didn't work

Answer 1

Your code seems to be fine, so I think the problem will rather be in your theme. Are you developing your own theme too? The wp_head function calls in those files, which were hooked to wp_enqueue_scripts. It should be in the theme between the head tags, similarly as you see here: https://developer.wordpress.org/reference/functions/wp_head/#comment-900

Answer 2

I had the same problem... the thing is that you are using wp_enqueue_scripts, but if you want to load it in admin panel you have to use admin_enqueue_scripts instead...

The function should be called using the wp_enqueue_scripts action hook if you want to call it on the front-end of the site, like in the examples above. To call it on the administration screens, use the admin_enqueue_scripts action hook.

Answer 3

1)check the location of javascript file it must in correct directory.

2. The function is being called too early: The wp_enqueue_script function should be called after the wp_enqueue_scripts hook is fired. Make sure that you are calling this function in the correct hook.