withMountWhenInView

Use this decorator to create a component which will mount and destroy itself based on its visibility in the viewport.

Usage

import { Base, withMountWhenInView } from '@studiometa/js-toolkit';
import Component from './Component.js';

export default withMountWhenInView(Component, { threshold: [0, 1] });

Parameters

• Base (BaseConstructor): The Base class or a class extending it.
• options (IntersectionObserverInit): Options for the IntersectionObserver instance.

Return value

• BaseConstructor: A child class of the given class which will be mounted when visible and destroyed when invisible.

API

This decorator does not expose a specific API.

Examples

Simple usage

import { Base, withMountWhenInView } from '@studiometa/js-toolkit';

export default class Component extends withMountWhenInView(Base) {
  static config = {
    name: 'Component',
    log: true,
  };

  mounted() {
    this.$log('I am visible!');
  }

  destroyed() {
    this.$log('I am no longer visible.');
  }
}

With custom options

You can pass custom options for the IntersectionObserver instance by passing a second parameter to the withMountWhenInView function:

import { Base, withMountWhenInView } from '@studiometa/js-toolkit';

export default class Component extends withMountWhenInView(Base, {
  threshold: 0.5,
}) {
  static config = {
    name: 'Component',
  };

  mounted() {
    this.$log('I am visible!');
  }

  destroyed() {
    this.$log('I am no longer visible.');
  }
}

Or at the instance level in the data-option-intersection-observer attribute of the root element:

<div
  data-component="Component"
  data-option-intersection-observer='{
    "threshold": 0.5
  }'>
  ...
</div>