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JavaScript React by Example Building the Application Connecting the Confirm Guests Handler

Elizabeth Eymann
Elizabeth Eymann
12,196 Points

TypeError: props.toggleConfirmationAt is not a function

Hello, I see others have posted about this same problem. I tried going through their solutions but no luck. I don't know what I did wrong. My app works until I check the checkbox, then I get this syntax error: TypeError: props.toggleConfirmationAt is not a function. Can anyone help? Thanks!

In App.js

toggleConfirmationAt = (indexToChange) => 
      guests: this.state.guests.map((guest, index) => {
        if (index === indexToChange) {
          return {
            isConfirmed: !guest.isConfirmed
        return guest;

In GuestList.js:

import React from 'react';
import PropTypes from 'prop-types';
import Guest from './Guest';

const GuestList = (props) => {
  return (
    {props.guests.map((guest, index) => (
       handleConfirmation={() => props.toggleConfirmationAt(index)}

GuestList.propTypes = {
  guests: PropTypes.array.isRequired,
  toggleConfirmationAt: PropTypes.func.isRequired

export default GuestList;

In Guest.js:

import React from 'react';
import PropTypes from 'prop-types';

const Guest = props => {
  return (

Guest.propTypes = {
  name: PropTypes.string.isRequired,
  isConfirmed: PropTypes.bool.isRequired,
  handleConfirmation: PropTypes.func.isRequired

export default Guest;

1 Answer

Elizabeth Eymann
Elizabeth Eymann
12,196 Points

Ok I solved my own problem here...of course it was a typo!!!

Down in App.js, here was my problem. I fixed it and it works now :)