Hey I am new at blockchain development and I need to make contract name organization that create sessions contracts. I had already implemented the solidity code but I have a problem in front-end development. I can't call session contract methods. It give me this error

Uncaught (in promise) TypeError: r is not a function

My Solidity Code:-

pragma solidity 0.5.0;

contract Organization {

     address creator;
     event sessionnCreated(string name,address sessionAddress ,address creator);

       modifier onlyCreator(){
        require(msg.sender == creator);
     function createdSession(
      string memory _sessionName,
      string memory _description,
      uint _startTime,
      uint _endTime,
      address[] memory _lecturer,
      address[] memory _attendes
     ) public   returns(address) {

        Session sessionAddress = new Session(_sessionName , _description , _startTime , _endTime, _lecturer,_attendes );
        emit sessionnCreated(_sessionName,address(sessionAddress),creator);
        return address(sessionAddress);



contract Session {

      address public creator;  // The address of parent Organization

      string sessionName;
      string description;
      uint startTime;
      uint endTime;
      address[] lecturer;
      address[] attendes; 

      int[] result; 
      mapping(address => int) public attendes_feedback; //institution boardMembers
      modifier onTime(uint _startTime){
            require(now < _startTime);
      constructor (string memory _sessionName, string memory _description, uint _startTime,uint _endTime,address[] memory   _lecturer,address[] memory  _attendes) public onTime(_startTime){

              sessionName =  _sessionName;
              description = _description;
              startTime = _startTime;
              endTime = _endTime;
              attendes = _attendes;
              lecturer = _lecturer;

    function initAttendes(address[] memory _attendes) private{
           for(uint i=0 ; i < _attendes.length ; i++){
            attendes_feedback[_attendes[i]] = -1;

    function Time() public view returns (bool){
       return (now >=  startTime  && now <= endTime);          

    modifier checkTime(){
    function take_feedback(address _voter,uint8 _feedback)  public checkTime {
          require(attendes_feedback[_voter] != 0);
          attendes_feedback[_voter] = _feedback;

  function seeResult() public view returns(int[] memory){
          return result;

My js code:-

import Web3 from "web3";
import OrganizationArtifact from "../../build/contracts/Organization.json";

const App = {
    web3: null,
    account: null,
    meta: null,

    start: async function() {
        const { web3 } = this;

        try {
            // get contract instance
            const networkId = await web3.eth.net.getId();
            const deployedNetwork = OrganizationArtifact.networks[networkId];
            this.meta = new web3.eth.Contract(

            // get accounts
            const accounts = await web3.eth.getAccounts();
            this.account = accounts[0];

        } catch (error) {
            console.error("Could not connect to contract or chain.");

    //Create session
    createdSession: async function(_sessionName, _description, _startTime, _endTime, _lecturer, _attendes) {
        var contractAddress;
        var address;
        const { createdSession } = this.meta.methods;
        contractAddress = await createdSession(_sessionName, _description, _startTime, _endTime, _lecturer, _attendes).send({ from: this.account });
        var address = await createdSession(_sessionName, _description, _startTime, _endTime, _lecturer, _attendes).call();
        alert("Contract created successfully contact addresss is " + address);
  //Take Feedback
    takeVote: async function() {
        var _sessionName = $('#feedback_session_name').val();
        var _feedback = $('#feedback').val();
        const { takeVote } = this.meta.methods;
        await takeVote(_sessionName, _feedback).send({ from: this.account });
window.App = App;

window.addEventListener("load", function() {
    if (window.ethereum) {
        // use MetaMask's provider
        App.web3 = new Web3(window.ethereum);
        window.ethereum.enable(); // get permission to access accounts
    } else {
            "No web3 detected. Falling back to You should remove this fallback when you deploy live",
        // fallback - use your fallback strategy (local node / hosted node + in-dapp id mgmt / fail)
        App.web3 = new Web3(
            new Web3.providers.HttpProvider(""),


Create Session function in organization contract work well because it's in organization contract but take_feedback function isn't working at all(it give this error "TypeError: r is not a function" when I call it in js file ).

If anyone could help me how to access methods of the child contract? Thanks in advance

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