Context Instances

  • Type: object
  • Origin: Nullstack Context
  • Availability: client
  • readwrite in client context

It gives you all active instances of the application.

💡 Active instances are the ones created and not yet terminated

As explained in instance key, keys play a big role in defining a unique identifier for components.

🔥 Nullstack trusts its developers to know what they are doing and exposes as much internal behavior for the programmer to do as it wishes, use with caution.

The default key for class components is a join between the class name and the dom depth like Counter/1.1 and are hard for humans to interact with.

The first component of your application will have the key application by default.

💡 keys define which instance will be used to render the component, you can use it to force a node to reinstantiate.

Adding an unique key to Counter makes it easier to access on instances list:

import Nullstack from 'nullstack';
import Counter from './Counter';
import AnyOtherComponent from './AnyOtherComponent';

class Application extends Nullstack {

  render() {
    return (
      <main>
        <Counter key="counter" />
        <AnyOtherComponent/>
      </main>
    )
  }

}

export default Application;
import Nullstack from 'nullstack';

class Counter extends Nullstack {

  value = 0;

  increment() {
    this.value++;
  }

  render() {
    return <p> Count: {this.value} </p>
  }

}

export default Counter;

You can access any methods and instance variables from counter instance on AnyOtherComponent:

import Nullstack from 'nullstack';

class AnyOtherComponent extends Nullstack {

  render({ instances }) {
    return (
      <button onclick={instances.counter.increment}>
        Add 1 to {instances.counter.value}
      </button>
    )
  }

}

export default AnyOtherComponent;

The use of instances unlocks unlimited custom behaviors like:

  • A notification icon at the navbar that can be updated from other components at certain actions
  • A toast component that can be invoked from anywhere in your application
  • A store system with custom dispatch methods similar to Redux
  • Something we haven't even imagined, dream on and post your ideas on GitHub!

Next step

⚔ Learn about the context environment.

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