ISOTOPE - Missing/Invalid Arguement Get Terms

Question

I am trying to use the isotope plugin for sorting on my taxonomy page and even though I don't know much about how to set it up, I tried using some advice found on here.

Wordpress and isotope filtering

I did so by taking this code

function isotope_categories() {

        $categories = get_categories();

        $html = '<ul class="filters option-set" data-option-key="filter">';
        $html .= '<li><a href="#filter" data-option-value="*" class="selected">All items</a></li>';

        foreach ($categories as $category) {

            $html .= "<li><a href='#filter' data-option-value='.category-{$category->category_nicename}'>{$category->cat_name}</a></li>";   
        }

        $html .= '</ul>';

        echo $html;
    }

and tried altering it so that it would work with get_terms (custom taxonomy). The code I ended up with is -

function isotope_categories() {

        $categories = get_terms();

        $html = '<ul class="filters option-set" data-option-key="filter">';
        $html .= '<li><a href="#filter" data-option-value="*" class="selected">All items</a></li>';

        foreach ($terms as $term) {

            $html .= "<li><a href='#filter' data-option-value='.category-{$term->name}'>{$term->name}</a></li>";   
        }

        $html .= '</ul>';

        echo $html;
    }

However when I use <?php isotope_categories() ?> in my taxonomy page I receive the following errors -

Warning: Missing argument 1 for get_terms(), called in html/wp-content/themes/lawcademy_theme/functions.php on line 1667 and defined in html/wp-includes/taxonomy.php on line 1165

Warning: Invalid argument supplied for foreach() in html/wp-content/themes/lawcademy_theme/functions.php on line 1672

How can I fix the code so that I don't get these errors?? Any help is appreciated. Thanks.

Answer 1

get_categories() does not require parameters, by default it will query the post type post and the taxonomy category. However, get_terms() require a taxonomy parameter.

Also, in the second function, you wrote:

 $categories = get_terms();

It should have been

$terms = get_terms('your_taxonomy');