Class AsyncPreloader

AsyncPreloader: assets preloader using ES2017 async/await and fetch.

It exports an instance of itself as default so you can:

import Preloader from "async-preloader";

await Preloader.loadItems([]);

to use directly as a singleton or

import { AsyncPreloader as Preloader } from "async-preloader";

const preloader = new Preloader();
await preloader.loadItems([]);

if you need more than one instance.

Constructors

constructor

Properties

defaultBodyMethod defaultLoader items domParser loaders

Methods

loadArrayBuffer loadAudio loadBlob loadFont loadFormData loadImage loadItem loadItems loadJson loadManifest loadText loadVideo loadXml fetchItem getFileBaseName getFileExtension getFileName getLoaderKey getMimeType getProp

Constructors

constructor

Properties

defaultBodyMethod

defaultBodyMethod: BodyMethod = "blob"

Default body method to be called on the Response from fetch if no body option is specified on the LoadItem

defaultLoader

defaultLoader: LoaderKey = LoaderKey.Text

Default loader to use if no loader key is specified in the LoadItem or if the extension doesn't match any of the AsyncPreloader.loaders extensions

items

items: Map<string, LoadedValue> = ...

Object that contains the loaded items

Static Private domParser

domParser: DOMParser = ...

DOMParser instance for the XML loader

Static Private loaders

loaders: Map<LoaderKey, LoaderValue> = ...

Loader types and the extensions they handle

Allows the omission of the loader key in a LoadItem.loader for some generic extensions

Methods

loadArrayBuffer

  • loadArrayBuffer(item): Promise<ArrayBuffer>

  • Load an item and parse the Response as arrayBuffer

    Parameters

    Returns Promise<ArrayBuffer>

    Fulfilled value of parsed Response

loadAudio

  • loadAudio(item): Promise<LoadedValue>

  • Load an item in one of the following cases:

    • item's "loader" option set as "Audio"
    • item's "src" option extensions matching the loaders Map
    • direct call of the method

    Parameters

    Returns Promise<LoadedValue>

    Fulfilled value of parsed Response according to the "body" option. Defaults to an HTMLAudioElement with a blob as srcObject or src.

loadBlob

  • loadBlob(item): Promise<Blob>

  • Load an item and parse the Response as blob

    Parameters

    Returns Promise<Blob>

    Fulfilled value of parsed Response

loadFont

  • loadFont(item): Promise<string | FontFace>

  • Load a font via FontFace or check a font is loaded via FontFaceObserver instance

    Parameters

    • item: LoadItem

      Item to load (id correspond to the font family name).

    Returns Promise<string | FontFace>

    Fulfilled value with FontFace instance or initial id if no src provided.

loadFormData

  • loadFormData(item): Promise<FormData>

  • Load an item and parse the Response as formData

    Parameters

    Returns Promise<FormData>

    Fulfilled value of parsed Response

loadImage

  • loadImage(item): Promise<LoadedValue>

  • Load an item in one of the following cases:

    • item's "loader" option set as "Image"
    • item's "src" option extensions matching the loaders Map
    • direct call of the method

    Parameters

    Returns Promise<LoadedValue>

    Fulfilled value with a decoded HTMLImageElement instance of or a parsed Response according to the "body" option. Defaults to a decoded HTMLImageElement.

loadItem

loadItems

  • loadItems(items): Promise<LoadedValue[]>

  • Load the specified manifest (array of items)

    Parameters

    • items: string[] | LoadItem[]

      Items to load

    Returns Promise<LoadedValue[]>

    Resolve when all items are loaded, reject for any error

loadJson

  • loadJson(item): Promise<JSON>

  • Load an item and parse the Response as json

    Parameters

    Returns Promise<JSON>

    Fulfilled value of parsed Response

loadManifest

  • loadManifest(src, key?): Promise<LoadedValue[]>

  • Load a manifest of items

    Parameters

    • src: string

      Manifest src url

    • key: string = "items"

      Manifest key in the JSON object containing the array of LoadItem.

    Returns Promise<LoadedValue[]>

loadText

  • loadText(item): Promise<string>

  • Load an item and parse the Response as text

    Parameters

    Returns Promise<string>

    Fulfilled value of parsed Response

loadVideo

  • loadVideo(item): Promise<LoadedValue>

  • Load an item in one of the following cases:

    • item's "loader" option set as "Video"
    • item's "src" option extensions matching the loaders Map
    • direct call of the method

    Parameters

    Returns Promise<LoadedValue>

    Fulfilled value of parsed Response according to the "body" option. Defaults to an HTMLVideoElement with a blob as srcObject or src.

loadXml

  • loadXml(item): Promise<LoadedXMLValue>

  • Load an item in one of the following cases:

    • item's "loader" option set as "Xml"
    • item's "src" option extensions matching the loaders Map
    • direct call of the method

    Parameters

    • item: LoadItem

      Item to load (need a mimeType specified or default to "application/xml")

    Returns Promise<LoadedXMLValue>

    Result of Response parsed as a document.

Static Private fetchItem

  • fetchItem(item): Promise<Response>

  • Fetch wrapper for LoadItem

    Parameters

    Returns Promise<Response>

    Fetch response

Static Private getFileBaseName

  • getFileBaseName(path): string

  • Get file base name

    Parameters

    • path: string

    Returns string

Static Private getFileExtension

  • getFileExtension(path): string

  • Get file extension

    Parameters

    • path: string

    Returns string

Static Private getFileName

  • getFileName(path): string

  • Get file name

    Parameters

    • path: string

    Returns string

Static Private getLoaderKey

  • getLoaderKey(extension): LoaderKey

  • Retrieve loader key from extension (when the loader option isn't specified in the LoadItem)

    Parameters

    • extension: string

    Returns LoaderKey

Static Private getMimeType

  • getMimeType(loaderKey, extension): DOMParserSupportedType

  • Retrieve mime type from extension

    Parameters

    Returns DOMParserSupportedType

Static Private getProp

  • getProp(object, path): any

  • Get an object property by its path in the form 'a[0].b.c' or ['a', '0', 'b', 'c']. Similar to lodash.get.

    Parameters

    • object: unknown

      Object with nested properties

    • path: string | string[]

      Path to the desired property

    Returns any

    The returned object property

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constructordefaultBodyMethoddefaultLoaderitemsdomParserloadersloadArrayBufferloadAudioloadBlobloadFontloadFormDataloadImageloadItemloadItemsloadJsonloadManifestloadTextloadVideoloadXmlfetchItemgetFileBaseNamegetFileExtensiongetFileNamegetLoaderKeygetMimeTypegetProp