`onQueryStateChange` callback

[olistic]

This is a feature proposal.

Hey! I really enjoy the declarative approach of react-media, but I just hit a wall in my use case where having a way of doing some imperative programming would really help.

The problem

When the width is enough, my screen is horizontally split in two. To the left, I have component Code and to the right I have two tabs with components Readme and Play. Just one tab can be active at a time, and which one it is is tracked in the component's state:

Now, when the width is not enough, I don't split the screen and instead convert Code into another tab:

The problem is that, when the width of the screen changes (because of orientation change, for example), if tab Code was active and then the tab ceases to exist, I end up with something like this:

I'd like to be able to modify the state upon a media query state change, to be able to change the active tab.

My proposal

Add an onQueryStateChange callback as a prop to the <Media> component, so imperative stuff can be done there. onQueryStateChange would receive the matches state as a parameter.

In my use case, that would allow me to do:

class MyComponent extends React.Component {
  state = {
    activeTab: 'README';  // Active tab defaults to 'README'.
  };

  handleQueryStateChange = e => { // e is a MediaQueryListEvent instance.
    // If 'CODE' was the active tab and it would cease to exist,
    // make 'README' the active tab.
    if (this.state.activeTab === 'CODE' && !e.matches) {
      this.setState({ activeTab: 'README' });
    }
  };

  render() {
    return (
      <Media
        query={...}
        onQueryStateChange={this.handleQueryStateChange}
      >
        ...
      </Media>
    );
  }
}

If this is something you would consider adding to react-media, I'm happy to work on a PR for it. Thanks!

[mjackson]

Sorry for the slowness here. This sounds good. Let's call it onChange for brevity.