How to get the data from React Context Consumer outside the render

Question

I am using the new React Context API and I need to get the Consumer data from the Context.Consumer variable and not using it inside the render method. Is there anyway that I can achieve this?

For examplify what I want:

console.log(Context.Consumer.value);

What I tested so far: the above example, tested Context.Consumer currentValue and other variables that Context Consumer has, tried to execute Context.Consumer() as a function and none worked.

Any ideas?

I tested a similar approach, there's a `_currentValue` and `_defaultValue` members inside a consumer, but accessing `Context.Consumer._currentValue.value` always returns the default value or undefined if not properly inited. — keul, Jun 06 '18 at 10:06
I create a HOC https://www.npmjs.com/package/react-context-consumer-hoc that achieves this by wrapping your component prior to exporting it. It might NOT be what you are looking for, but I want to put it here because this is where I ended up the first time I had this issue. — pgarciacamou, Jun 22 '18 at 18:19

score 30 · Answer 1 · edited Mar 25 '19 at 20:56

30

Update

As of React v16.6.0, you can use the context API like:

class App extends React.Component {
    componentDidMount() {
       console.log(this.context);
    }
    render() {
       // render part here
       // use context with this.context
    }
}
App.contextType = CustomContext

However, the component can only access a single context. In order to use multiple context values, use the render prop pattern. More about Class.contextType.

If you are using the experimental public class fields syntax, you can use a static class field to initialize your contextType:

class MyClass extends React.Component {
  static contextType = MyContext;
  render() {
    let value = this.context;
    /* render something based on the value */
  }
}

Render Prop Pattern

When what I understand from the question, to use context inside your component but outside of the render, create a HOC to wrap the component:

const WithContext = (Component) => {
  return (props) => (
      <CustomContext.Consumer>
           {value =>  <Component {...props} value={value} />}
      </CustomContext.Consumer>
  )
}

and then use it:

class App extends React.Component {
    componentDidMount() {
       console.log(this.props.value);
    }
    render() {
       // render part here
    }
}
export default WithContext(App);

edited Mar 25 '19 at 20:56

danronmoon

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answered Apr 17 '18 at 06:06

Shubham Khatri

211,155
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4

This is more or less the official question from https://reactjs.org/docs/context.html#accessing-context-in-lifecycle-methods However I found this solution a lot complex and boilerplate than old `this.context` of React 15. – keul Jun 06 '18 at 09:41
1

@LucaFabbri, from version 16.6.0 version of React onwards, the context API can be used using `this.context` so no more BoilerPlate to it – Shubham Khatri Nov 23 '18 at 05:17
@ShubhamKhatri, I don't know why the 16.6+ `App.contextType = CustomContext`didn't work for me. It didn't make anything. And the `static contextType` only works when you have 1 context. However, the WithContext worked like a charm! Claps to you. – Aldo Apr 05 '19 at 13:32
@ShubhamKhatri, `static contextType = MyContext;` what's MyContext ? – Menai Ala Eddine - Aladdin May 02 '20 at 00:12
@MenaiAlaEddine MyContext is the context you create using React.createContext – Shubham Khatri May 02 '20 at 04:30

score 4 · Answer 2 · answered Oct 07 '20 at 06:13

4

You can achieve this in functional components by with useContext Hook.

You just need to import the Context from the file you initialised it in. In this case, DBContext.

 const contextValue = useContext(DBContext);

answered Oct 07 '20 at 06:13

Ankur Kedia

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qwertzguy · Answer 3 · 2020-02-23T20:05:24.463

2

You can via an unsupported getter:

YourContext._currentValue

Note that it only works during render, not in an async function or other lifecycle events.

edited Feb 23 '20 at 20:05

answered Jan 27 '20 at 03:21

qwertzguy

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score 0 · Answer 4 · answered Oct 12 '19 at 09:32

This is how it can be achieved.

 class BasElement extends React.Component {
  componentDidMount() {
    console.log(this.props.context);
  }

  render() {
    return null;
  }
}

const Element = () => (
  <Context.Consumer>
    {context =>
      <BaseMapElement context={context} />
    }
  </Context.Consumer>
)

Sebastien Horin · Answer 5 · 2020-12-04T10:52:03.613

0

For the @wertzguy solution to work, you need to be sure that your store is defined like this:

// store.js
import React from 'react';

let user = {};
const UserContext = React.createContext({
  user,
  setUser: () => null
});

export { UserContext };

Then you can do

import { UserContext } from 'store';

console.log(UserContext._currentValue.user);

edited Dec 04 '20 at 10:52

answered Nov 19 '20 at 22:30

Sebastien Horin

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How to get the data from React Context Consumer outside the render

5 Answers5

Update

Render Prop Pattern

Linked