WooCommerce - is Product in Cart

functions.php

<?php

function is_product_in_cart( $prodID ) {
    $cartID = WC()->cart->generate_cart_id( $prodID );
    $in_cart = WC()->cart->find_product_in_cart( $cartID );
    if ( $in_cart ) {
        return true;
    }
    return false;
}


/* USAGE: 
-------------------- */

// Product ID
$myProd = 1234;

// See if Product is in Cart
if ( is_product_in_cart( $myProd ) {
    // do stuff
    return true;
}

?>