invp_unprefix_meta_key

Filter Hook: Maybe append to the meta_query if it is already set. If we are sorting by make, then we want to also add a secondary sort of model and a tertiary sort of trim. That’s what users want. Apply the same logic to sorts by year and model.

invp_prefix_meta_key

Filter Hook: Determine if this meta field should be sorted as a number 1. Parse out the meta key name from $pieces[‘where’] 2. Run it through INVP::meta_value_is_number