While looping API response in accordion menu data missing in Angular4

Question

I am tying to bind the api response (json) in accordion menu ,Here everything is working fine but in accordion I have category,group and subgroup .

In category there is

Answer 1

Use this code:

            

                

                    

                        

                            
                                {{group?.CAMD_PRGRP_DESC}}
                            
                        
                        

                            

                                {{subgroup?.CAMD_PRSGRP_DESC}}