this.props.xxxx is not a function - reactjs

Question

class UserForm extends React.Component {
constructor(props) {
super(props);
const { user } = props;
}
_cancelForm() {
this.props.onCancel();
}
render() {
return (
<button onClick={this._cancelForm.bind(this)}> Cancel </button>
);
}
}
class UserCreate extends React.Component {
_navigateToLogin() {
console.log("hi")
}
render() {
return (
<div>
<UserForm onCancel={this._navigateToLogin.bind(this)}/>
</div>
);
}
}
ReactDOM.render(
<UserCreate/>,
document.getElementById('root')
);
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.8.4/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.8.4/umd/react-dom.production.min.js"></script>
<div id="root"></div>
import React from 'react'
import { withRouter } from 'react-router-dom';
import UserForm from './UserForm'
import UsersService from '../services/UsersService'
class UserCreate extends React.Component{
_navigateToLogin() {
this.props.history.push('/homepage');
}
async _saveUser(user) {
await UsersService.createUser(user);
this._navigateToLogin();
}
render() {
return(
<div>
<UserForm
onCancel={this._navigateToLogin.bind(this)}
onSubmit={this._saveUser.bind(this)}
/>
</div>
);
}
}
export default withRouter(UserCreate)
import React from 'react'
import {
Button
} from '#material-ui/core'
export default class UserForm extends React.Component {
constructor(props) {
super(props);
const { user } = props;
this.state = {
...
}
_handleFormSubmit() {
const user = {
...
};
this.props.onSubmit(user);
}
_cancelForm() {
this.props.onCancel();
}
render () {
return (
<div style={{ width: '100%', height: 'auto', position: 'fixed', minWidth: '100%', minHeight: '100%', backgroundColor: '#50617C' }}>
<Button size="small" onClick={ this._cancelForm.bind(this) }>Back</Button>
<Button size="small" onClick={ this._handleFormSubmit.bind(this) }>Create</Button>
</div>
)
}
}
The error is present when I click the "Back" button on CreateAccountForm, it returns an error that says that the onCancel function is not a function. I'm sending it on the UserCreate by binding and I'm calling it on the function _cancelForm(). I was thinking that the error is that I'm missing something in the constructor according to some react documentation, I used before this method and it worked, right now I don't know what's happening.

Answer 1

The code you posted does not demonstrate the error, below is your code and it works just fine.
class UserForm extends React.Component {
constructor(props) {
super(props);
}
_cancelForm() {
this.props.onCancel();
}
render() {
return (
<button onClick={this._cancelForm.bind(this)}>
cancel
</button>
);
}
}
class UserCreate extends React.Component {
_navigateToLogin() {
console.log('in navigate login');
}
render() {
return (
<div>
<UserForm
onCancel={this._navigateToLogin.bind(this)}
/>
</div>
);
}
}
ReactDOM.render(
<UserCreate />,
document.getElementById('root')
);
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.8.4/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.8.4/umd/react-dom.production.min.js"></script>
<div id="root"></div>
Can you provide a minimal snippet that reproduces the error you are getting?
You also don't need to bind the handler if you use arrow functions. For example:
_navigateToLogin = () => {//arrow function is automatically bound to this
console.log('in navigate login');
};
and
<UserForm onCancel={this._navigateToLogin} />