Function and usage of is_error() in wordpress

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    2024-01-08T21:17:43+00:00

    The is_error() function in WordPress is a utility function used to check if a given variable is a WordPress Error object. WordPress Error objects are instances of the WP_Error class, which is used throughout WordPress to handle error messages and error data.

    Function Signature

    is_error( $thing )
    

    Parameters

    • $thing (mixed): The variable you want to check. This can be anything: a string, an array, an object, etc.

    Return Values

    • True: if $thing is an instance of the WP_Error class.
    • False: if $thing is not an instance of the WP_Error class.

    Usage

    The is_error() function is particularly useful when you're dealing with functions that might return either a regular result or a WP_Error object. It helps in writing cleaner code by quickly checking if the returned value is an error.

    Sample Usage

    Consider a scenario where you're using a WordPress function that might return an error, such as get_category().

    $category = get_category( $category_id );
    
    if ( is_error( $category ) ) {
        // Handle error, maybe display an error message
        echo 'Error: ' . $category->get_error_message();
    } else {
        // No error, proceed with using $category
        echo 'Category name: ' . $category->name;
    }
    

    In this example, we first try to get a category using get_category(). We then check if the returned $category is an error using is_error(). If it's an error, we handle it (for example, by displaying the error message). If it's not an error, we proceed with our normal operations, such as displaying the category name.

    Note

    The is_error() function is not a native WordPress function. Typically, developers check for an error using is_wp_error() instead. The is_wp_error() function performs a similar check, determining whether the provided value is an instance of WP_Error. However, if you're using a custom implementation named is_error(), the concept remains the same, but make sure to check how it's defined in your codebase.

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