Basically my issue is that the get_field() function doesn’t format the default value if meta doesn’t exist for the post…
1. So I have a select field with choices that are loaded dynamically using the acf/load_field filter.
2. I then set a default value for the same field using acf/load_value.
3. And finally, I format the values using acf/format_value.
For example, I have a field named my_field:
1. Loading values.
add_filter( 'acf/load_field/name=my_field', function( $field ) {
// Get category terms, for this post
$terms = get_the_terms( get_the_ID(), 'categories' );
if ( !empty( $terms ) && !is_wp_error( $terms ) ) {
// Reset choices array
$field[ 'choices' ] = [];
// Enable field
$field[ 'disabled' ] = false;
// Add terms to choices array
foreach ( $terms as $category ) {
$field[ 'choices' ][ $category->term_id ] = $category->name;
}
}
// Disable field if no choices
if ( empty( $field[ 'choices' ] ) ) {
// Set "placeholder" text
$field[ 'choices' ] = [ 'This post has no categories' ];
// Disable field
$field[ 'disabled' ] = true;
}
return $field;
}, 10, 1 );
2. Setting default.
add_filter( 'acf/load_value/name=my_field', function( $value, $post_id, $field ) {
$terms = get_the_terms( $post_id, 'categories' );
$term_ids = [];
if ( !empty( $terms ) && !is_wp_error( $terms ) ) {
$term_ids = array_map( function( $term ) {
return $term->term_id;
}, $terms );
}
// Value does not exists
if ( !in_array( $value, $term_ids ) && !empty( $term_ids ) ) {
// Get the last term in array and set as default
if ( $last_term = end( $term_ids ) ) {
return $last_term;
}
}
return $value
}, 10, 1 );
3. Formatting value.
add_filter( 'acf/format_value/name=my_field', function( $value, $post_id, $field ) {
if ( !empty( $value ) ) {
if ( $term = get_term_by( 'id', $value, 'categories' ) ) {
return $term->name;
}
}
return null;
}, 10, 1 );
Now what this does is..
1. Fill my select field with the saved category terms of the current post with the term_id as the value and the term name as the label.
2. Then it validates the field value. If it doesn’t match a category term I set the default value to the last category in the get_the_terms array.
3. Format the value to return the category name not the term_id.
Now we have default values for this field for all existing posts. But when using the get_field or the_field function we do not get the formatted value which we expect the be the term name. We actually get the term_id.
Looking at the get_field function in source (includes/api/api-template.php).
function get_field( $selector, $post_id = false, $format_value = true ) {
// filter post_id
$post_id = acf_get_valid_post_id( $post_id );
// get field
$field = acf_maybe_get_field( $selector, $post_id );
// create dummy field
if( !$field ) {
$field = acf_get_valid_field(array(
'name' => $selector,
'key' => '',
'type' => '',
));
// prevent formatting
$format_value = false;
}
// get value for field
$value = acf_get_value( $post_id, $field );
// format value
if( $format_value ) {
// get value for field
$value = acf_format_value( $value, $post_id, $field );
}
// return
return $value;
}
You can see the function acf_maybe_get_field is called, this tries to find the field based on meta values but we don’t have meta values yet so this returns false. And now because this returns false we fall into the // create dummy field if statement. In here we can see that the function is forcing formatting to be ignored $format_value = false;. We have no way of bypassing this.
TL;DR
get_field() ignores formatting for default values. Can this be removed or a workaround added?
Hope this all makes sense.
