flight-with-child-components

A Flight mixin for nesting components by coupling their life-cycles, making sure that a component and its children are torn down together.

A component that intends to initialize child components should mix in withChildComponents and attach the children using this.attachChild.

The child will be passed an even to listen out for – when it's triggered, the child will teardown. withChildComponents mixin adds a unique event name to the parent (this.childTeardownEvent) for this use, but you can manually specify a teardownOn event name in the child's attrs.

This construct supports trees of components because, if the child also mixes in withChildComponents, it's childTeardownEvent will be fired before it is torn down, and that will teardown any further children in a cascade.

Installation

npm install --save flight-with-child-components

Use

In the parent component, mixin withChildComponents into the parent.

defineComponent(Component, withChildComponents);

This will add a generated this.childTeardownEvent property to the component — like _teardownEvent7 — which will then be used to coordinate teardown with any "child" components.

You don't need to use the childTeardownEvent manually: instead, use the this.attachChild method:

this.attachChild(ChildComponent, this.select('someChild'));

This will do some magic to make sure that the ChildComponent instance does teardown with (actually, just before) the parent.

Here's a full example:

var withChildComponents = require('fight-with-child-components');
var ChildComponent = require('some/child');
var AnotherChildComponent = require('some/other/child');

return defineComponent(parentComponent, withChildComponents);

function parentComponent() {

  this.after('initialize', function () {
    // this.attachChild does all the work needed to support nesting
    this.attachChild(ChildComponent, this.select('someChild'));

    // it supports the same API as 'attachTo'
    this.attachChild(AnotherChildComponent, '.another-child', {
      someProperty: true,
      // You can manually specify a teardown event
      teardownOn: 'someTeardownEvent'
    });


    setTimeout(() => {
      this.trigger('someTeardownEvent');
    }, 1000);
  });
}

As in the above example, you can specify a custom teardown event:

this.attachChild(AnotherChildComponent, '.another-child', {
  teardownOn: 'someTeardownEvent'
});

This allows you to manually cause the teardown of that child.

Importantly, this overrides the parent-child teardown behaviour. If you want to keep it, you must additionally supply the childTeardownEvent:

this.attachChild(AnotherChildComponent, '.another-child', {
  teardownOn: `someTeardownEvent ${this.childTeardownEvent}`
});

Non-Flight code

withChildComponents provides a utility to help you coordinate Flight-component teardown from non-Flight code.

First, import the attach method:

const { attach } = require('flight-with-child-components');

You can use attach to attach Flight components like you would with attachTo, but you also can grab the resulting teardown event from the returned object:

const { teardownEvent } = attach(Component, '.some-node');

You can then manually tear the component down using a jQuery event.

$(document).trigger(teardownEvent);

Like with attachChild, you can supply a custom teardownOn event name:

const { teardownEvent } = attach(Component, '.some-node', {
  teardownOn: 'someTeardownEvent'
});

In this example, teardownEvent will be someTeardownEvent.

Teardown hooks

To perform cleanup tasks around child teardown events, there are two methods you can "hook" with advice: willTeardownChild and didTeardownChild.

this.before('willTeardownChild', function () {
  // The childTeardownEvent has not yet fired, so you can do any extra cleanup you need
  // before your child components disappear
});

this.before('didTeardownChild', function () {
  // The childTeardownEvent has now fired and the child components will have run teardown.
  // This is the time to do final cleanup.
});

Development

To develop this module, clone the repository and run:

$ yarn && yarn test

If the tests pass, you have a working environment. You shouldn't need any external dependencies.

Contributing to this project

Anyone and everyone is welcome to contribute. Please take a moment to review the guidelines for contributing.

• Bug reports
• Feature requests
• Pull requests