Wordpress Plugin : Multiple values against same setting - php

Question

I am writing a plugin for category discounts. In Plugin Setting page, I have a Category and Discount_percentage fields. I am rending these as followings
function cat_slug_render( ) {
$options = get_option( 'slug-configuration' );
?>
<input type='text' size="50" name='slug-configuration[cat_slug]' value='<?php echo $options['cat_slug']; ?>'>
<?php
}
and defining the option as
add_settings_field(
'cat_slug', //id
'category Slug', //title
'cat_slug_render', // callable
'slug-configuration', // page
'configuration' // section
);
everything else is fine. I can save the settings, can retrieve it, can update it and all.
However, I can save just ONE value. My aim is to save multiple values using the same fields.
But I am confused here how can I do it. My ultimate goal is as follows
input cat slug
Input discount
Press save
this will insert a New record each time this process is done
any guidance or help is highly appreciated!

Answer 1

You can add to [cat_slug] as an array during save by using [] in the name attribute:
function cat_slug_render( ) {
$options = get_option( 'slug-configuration', array() );
?>
<input type='text' size="50" name='slug-configuration[cat_slug][]' value='<?php echo esc_html( $options['cat_slug'][0] ?? '' ); ?>'>
<?php
}
However, you'll have to decide which value should be pre-loaded into the field if you are going to save multiple values. The first? The last? I've added [0] to the value, which should show the first, but if you want the most recent you could do something like:
function cat_slug_render( ) {
$options = get_option( 'slug-configuration', array() );
$last_key = array_key_last( $options );
?>
<input type='text' size="50" name='slug-configuration[cat_slug][]' value='<?php echo esc_html( $options['cat_slug'][$last_key] ?? '' ); ?>'>
<?php
}
Obviously make sure to update your sanitizer function if you try this, and note that value should be secured using esc_html() as well as your preferred method of isset (I've used ?? from PHP 7 or higher) if you want to prevent errors when nothing has been saved.
To display or use the values you've saved, you can use a foreach loop on the [cat_slug] array key:
$options = get_option( 'slug-configuration', array() )[cat_slug] ?? array();
foreach( $options as $option ) {
// Do stuff.
}