How to use pre_field filter in WordPress

pre_field filter

The dynamic portion of the hook name, $field, refers to the post field name.

To use the pre_field filter, first you have to register it using add_filter. You can write this code into the functions.php of your activated theme or in a custom WordPress Plugin.

We at WePlugins always prefer to create a custom WordPress Plugin while using hooks so nothing breaks when you update your WordPress Theme in the future.

In the below live example, we have defined a function weplugins_modify_pre_field_defaults which takes 1 parameter, and we registered it using add_filter. The first parameter pre_field is the name of the hook, the second parameter weplugins_modify_pre_field_defaults is the name of the function which needs to be called, the third parameter is the priority of calling the hook if the same hook is used multiple times, and the last parameter is the number of arguments (if any) to be passed in the registered function.

Sometimes, you have to remove a registered hook so you can use remove_filter to remove the pre_field filter.

Parameters

Below, the 1 parameter is required to use this hook.

• $value : (mixed) Value of the post field.

Live Example

apply_filters( "pre_{$field}", mixed $value )

Below is an example of how you can use this hook.

Example 1: Modify the Field Value

This example demonstrates how to modify the value of a field before it is saved.

    function weplugins_modify_pre_field_defaults($value) { 
        // Update the $value variable according to your website requirements and return this variable.
        // You can modify the $value variable conditionally too if you want.
        return $value; 
    }
    // add the filter
    add_filter( "pre_field", "weplugins_modify_pre_field_defaults", 10, 1 );
    

Example 2: Conditional Modification

In this example, we modify the value conditionally based on specific criteria.

    function weplugins_modify_pre_field_defaults($value) { 
        if ($value == 'specific_value') {
            $value = 'new_value';
        }
        return $value; 
    }
    // add the filter
    add_filter( "pre_field", "weplugins_modify_pre_field_defaults", 10, 1 );
    

Example 3: Removing the Hook

To remove a hook callback, use the example below.

    // remove the filter
    remove_filter( "pre_field", "weplugins_modify_pre_field_defaults", 10, 1 );
    

Please make sure to provide the same callback function name, priority, and number of arguments while removing the hook callback.

Contact Us

If you’re having any trouble using this hook, please contact our WordPress Development Team and we’d be happy to assist you.