@mangoweb/scripts-base

@mangoweb/scripts-base

The manGoweb template for scripts employed on small to medium sized projects.

Installation

$ npm install @mangoweb/scripts-base

⚠️ You might want to also fix the package version so that any potential future backwards incompatibilities don't break your build. This package is generally intended for live development with the occasional BC break. Should that affect your application because you failed to fix the version, that's on you.

Usage

How to use a component

In your index.ts file (or equivalent), use:

import { initializeComponents } from '@mangoweb/scripts-base'

import { MyComponent } from './components/MyComponent'

initializeComponents(
	[
		MyComponent
	],
	'initComponents'
)

In your template:

<script>
	window.initComponents = (window.initComponents || []).push({
		name: 'MyComponent', // As specified by `displayName`
		place: '#myDiv', // A selector or an element, e.g. `document.body`
		data: { // Any data, as required by the component
			foo: 123
		}
	})
</script>

How to write a component

You must:

• Inherit from Component
• Define static componentName: string

import { Component, DelegateEvent, EventListeners } from '@mangoweb/scripts-base'

interface MyComponentData {
	foo: number
}

export class MyComponent extends Component<MyComponentData> {
	public static componentName = 'MyComponent'

	protected getListeners = (): EventListeners => [
		['click', this.handleClick],
		['click', '.delegateSelector', this.handleDelegateClick],
		// …
	]

	// The type of the argument depends on the actual event.
	// It could also be, for instance, a KeyboardEvent
	private handleClick(event: MouseEvent) {
		console.log('clicked', this.data.foo)
	}

	// Careful: this only works for events that bubble.
	private handleDelegateClick(event: DelegateEvent<'click'>) {
		console.log('delegate target', event.delegateTarget)
	}
}

The Component superclass accepts up to three generic parameters, all of which are optional. The first one, the structure of data, defaults to {}. The second one is the type of el. It defaults to HTMLElement but is useful to change when we want to assert that it is something else (e.g. Window, HTMLBodyElement, SVGElement, etc.).

The last parameter should only be necessary to change in very extreme situations. It is the map from supported event types to their respective Event objects. It should be inferred from the type of el, although it may be necessary to change, should the standard library prove to be incomplete.

The EventListeners return type of getListeners optionally accepts the same two parameters as the last two of Components. It may be necessary to specify one or both if inference fails.

Life-cycle methods

The following happens to your component during initialization (in that order):

1. The constructor is called (if it exists) as your component is instantialized.
2. Event listeners are attached
3. The init method is called (if it exists)

You typically don't need to implement a constructor but it can be useful to avoid TS2564.

Failed initialization

If for whatever reason you decide that the component is unable to run, just throw a ComponentInitializationError from either the constructor or the init method. You don't need to worry about any impact on production environment ‒ the error is always caught and its message only displayed when DEBUG is true.

Valid reasons for yielding and error include:

• Invalid data supplied
• A crucial element in the DOM is not found
• A crucial API is not present

More specific el

Optionally, you can also make an assertion that the element the component is attached to is an instance of a more specific interface than HTMLElement. To that end, you may supply the second generic parameter.

For example, to attach your component on a <form>, you can use Component<MyComponentData, HTMLFormElement>.

To achieve something similar for el's children, you can use getChild or getChildren:

const link: HTMLAnchorElement = this.getChild('.myLink', HTMLAnchorElement)

Property defaults

To get a property value with a default, you can use getProp. For example:

const isEnabled = this.getProp('isEnabled', true)

Pre-defined Components

You can import these and use them via initializeComponents side by side with your regular components (baring any potential naming conflicts):

import { Shapes } from `@mangoweb/scripts-base`
import { InView } from `@mangoweb/in-view`

There are currently these:

• Emitter
• InView
• Shapes