CODEWITHSUNDEEP
reactjsecmascript-6
skozz
skozz

Reputation: 2720

ReactJS with ES6: this.props is not a function when I communicate two components

I'm working with ReactJS with ES6, but I have some problems to communicate child > parent through props. Example of my approach:

class SearchBar extends React.Component {
  handler(e){
    this.props.filterUser(e.target.value);
  }

  render () {
  return <div>
    <input type='text' className='from-control search-bar' placeholder='Search' onChange={this.handler} />
  </div>
  }
}


export default class User extends React.Component {
  constructor(props) {
    super(props);
    this.state = {name: '', age: '', filter: ''};
  } 

  filterUser(filterValue){
    this.setState({
      filter: filterValue
    });
  }

  render() {
    return <div>
      <SearchBar filterUser={this.filterUser} />
      <span>Value: {this.state.filter}</span>
    </div>
  }
}

This returns Uncaught TypeError: this.props.filterUser is not a function.

Any idea? Binding maybe?

[EDIT] Solution (Thanks @knowbody & @Felipe Skinner):

I was missing binding in my constructor. Binding in the SearchBar constructor works perfectly.

Using React.createClass() (ES5), it automatically does bindings to this for your functions. In ES6 you need bind this manually. More info https://facebook.github.io/react/docs/reusable-components.html#es6-classes

Upvotes: 29

Views: 110468

Answers (4)

Mariusz Sidorowicz
Mariusz Sidorowicz

Reputation: 366

it can be also a mis export:

wrong: export function name ...

export default name

correct:

function name export default name

Upvotes: 0

T. Alves
T. Alves

Reputation: 21

In my case, I was importing the component the wrong way. I have the components "HomeAdmin" and "Register".

I had this in HomeAdmin.js: import { Register } from "/path/to/register"

Changed to this and worked: import Register from "/path/to/register"

Upvotes: 2

knowbody
knowbody

Reputation: 8276

You are missing binding in your constructor, also you don't need to pass props if you are not using them in the constructor. Also you need to import { PropTypes } from 'react' 

class SearchBar extends React.Component {

  constructor() {
    super();
    this.handler = this.handler.bind(this);
  }

  handler(e){
    this.props.filterUser(e.target.value);
  }

  render () {
    return (
      <div>
        <input type='text' className='from-control search-bar' placeholder='Search' onChange={this.handler} />
      </div>
    );
  }
}


export default class User extends React.Component {
  constructor() {
    super();
    this.filterUser = this.filterUser.bind(this);
    this.state = { name: '', age: '', filter: '' };
  } 

  filterUser(filterValue){
    this.setState({
      filter: filterValue
    });
  }

  render() {
    return ( 
      <div>
        <SearchBar filterUser={this.filterUser} />
        <span>Value: {this.state.filter}</span>
      </div>
    );
  }
}

Upvotes: 23

Felipe Skinner
Felipe Skinner

Reputation: 16616

When ur using React.createClass(), it automatically does bindings to this for your functions.

Since you're using the ES6 class syntax, you need to do those bindings by yourself. Here's two options:

render() {
    return <div>
      <SearchBar filterUser={this.filterUser.bind(this)} />
      <span>Value: {this.state.filter}</span>
    </div>
  }

Or you could bind it on your constructor like this:

constructor(props) {
    super(props);
    this.state = {name: '', age: '', filter: ''};
    this.filterUser = this.filterUser.bind(this);
  }

You can read about this on the docs: https://facebook.github.io/react/docs/reusable-components.html#es6-classes

Note that those two options are mutually exclusive.

Upvotes: 6

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