Magic term conversion with WordPress

convert-term.php

<?php
/*
Takes a term from many input types: object, id, slug, name
Returns one of many outputs: WP_Term (object), id (int), slug, name, or any WP_Term property

Example Inputs:

  smart_term_convert( 390, 'category', 'id' ); // Returns 390
  smart_term_convert( 'test-category', 'category', 'id' ); // Returns 390
  smart_term_convert( 'Test Category', 'category', 'id' ); // Returns 390
  smart_term_convert( $test_category_term, 'category', 'id' ); // Returns 390

Example Outputs:

  smart_term_convert( 390, 'category', 'object' );  // Returns OBJECT
  
  smart_term_convert( 390, 'category', 'term_id' ); // Returns (int) 390
  smart_term_convert( 390, 'category', 'id' );      // Returns (int) 390, alias of term_id
  
  smart_term_convert( 390, 'category', 'name' );    // Returns "Test Category"
  smart_term_convert( 390, 'category', 'title' );   // Returns "Test Category", alias of name
  
  smart_term_convert( 390, 'category', 'slug' );    // Returns "test-category"
  smart_term_convert( 390, 'category', 'url' );     // Returns "http://..../test-category/"
  
  smart_term_convert( 390, 'category', 'taxonomy' );// Returns "category", albeit pointless here

Test case:

echo '<pre>';
$keys = 'term_id|id|name|title|slug|url|object|taxonomy|term_taxonomy_id|fake_term_name';
foreach( explode('|', $keys) as $key ) echo $key, ': ', print_r( smart_term_convert( get_query_var( 'catalog' ), 'catalog', $key ), true ), "\n";
echo '</pre>';

Test case output:
term_id: 171
id: 171
name: FALL 15
title: FALL 15
slug: fall-15
url: http://.../catalog/fall-15/
object: stdClass Object
    [term_id] => 171
    [name] => FALL 15
    [slug] => fall-15
    [term_group] => 0
    [term_taxonomy_id] => 171
    [taxonomy] => catalog
    [description] => 
    [parent] => 0
    [count] => 8
    [filter] => raw
taxonomy: catalog
term_taxonomy_id: 171
fake_term_name: FALSE

*/
function smart_term_convert( $term_data, $taxonomy, $output = 'object' ) {
    if ( !$term_data ) return false;

    $term = false;

    // input: object
    if ( !$term && is_object( $term_data ) ) {
        $term = $term_data;
    }

    // input: slug, title
    if ( !$term && is_string( $term_data ) ) {
        $term = get_term_by( 'slug', $term_data, $taxonomy );
        if ( !$term ) $term = get_term_by( 'name', $term_data, $taxonomy );
    }

    // input: term_id
    if ( !$term && is_numeric( $term_data ) ) {
        $term = get_term_by( 'id', (int) $term_data, $taxonomy );
    }

    // No object found!
    if ( !$term ) return false;

    switch( strtolower($output) ) {
        case 'object':
            return $term;
            break;

        case 'name':
        case 'title':
            return $term->name;
            break;

        case 'term_id':
        case 'id':
            return $term->term_id;
            break;

        case 'slug':
            return $term->slug;
            break;

        case 'url':
            return get_term_link($term);
            break;

        default:
            if ( !$output ) return $term;
            if ( !property_exists($term, $output) ) return false;

            // other properties
            return $term->{$output};
            break;
    }
}