code: public static Node getRValueOfLValue(Node n) {
      Node parent = n.getParent();
      switch (parent.getToken()) {
        case ASSIGN:
        case ASSIGN_BITOR:
        case ASSIGN_BITXOR:
        case ASSIGN_BITAND:
        case ASSIGN_LSH:
        case ASSIGN_RSH:
        case ASSIGN_URSH:
        case ASSIGN_ADD:
        case ASSIGN_SUB:
        case ASSIGN_MUL:
        case ASSIGN_EXPONENT:
        case ASSIGN_DIV:
        case ASSIGN_MOD:
        case DESTRUCTURING_LHS:
          return n.getNext();
        case VAR:
        case LET:
        case CONST:
          return n.getLastChild();
        case OBJECTLIT:
        case CLASS_MEMBERS:
          return n.getOnlyChild();
        case FUNCTION:
        case CLASS:
          return parent;
        default:
          break;
      }
      return null;
    }
docs: Gets the r-value (or initializer) of a node returned by getBestLValue.