astro/packages/webapi

WebAPI

WebAPI lets you use Web APIs not present in Node v16 and later.

npm install @astrojs/webapi

import { polyfill } from '@astrojs/webapi'

polyfill(globalThis)

const t = new EventTarget()
const e = new CustomEvent('hello')

t.addEventListener('hello', console.log)

t.dispatchEvent(e) // logs `e` event from `t`

These APIs are combined from popular open source projects and configured to share implementation details. This allows their behavior to match browser expectations as well as reduce their combined memory footprint.

Features

• ByteLengthQueuingStrategy
• CanvasRenderingContext2D
• CSSStyleSheet
• CountQueuingStrategy
• CustomElementRegistry
• CustomEvent
• DOMException
• Document
• DocumentFragment
• Element
• Event
• EventTarget
• File
• FormData
• HTMLDocument
• HTMLElement
• HTMLBodyElement
• HTMLCanvasElement
• HTMLDivElement
• HTMLHeadElement
• HTMLHtmlElement
• HTMLImageElement
• HTMLSpanElement
• HTMLStyleElement
• HTMLTemplateElement
• HTMLUnknownElement
• Headers
• IntersectionObserver
• Image
• ImageData
• MediaQueryList
• MutationObserver
• Node
• NodeIterator
• OffscreenCanvas
• ReadableByteStreamController
• ReadableStream
• ReadableStreamBYOBReader
• ReadableStreamBYOBRequest
• ReadableStreamDefaultController
• ReadableStreamDefaultReader
• Request
• Response
• ShadowRoot
• Storage
• StyleSheet
• TransformStream
• TreeWalker
• WritableStream
• WritableStreamDefaultController
• WritableStreamDefaultWriter
• Window
• cancelAnimationFrame
• cancelIdleCallback
• clearTimeout
• fetch
• localStorage
• requestAnimationFrame
• requestIdleCallback
• setTimeout
• structuredClone
• URLPattern

Usage

You can use WebAPIs as individual exports.

import { Event, EventTarget, File, fetch, Response } from '@astrojs/webapi'

You can apply WebAPIs to an object, like globalThis.

import { polyfill } from '@astrojs/webapi'

polyfill(globalThis)

Polyfill Options

The exclude option receives a list of WebAPIs to exclude from polyfilling.

polyfill(globalThis, {
	// disables polyfills for setTimeout clearTimeout
	exclude: 'setTimeout clearTimeout',
})

The exclude option accepts shorthands to exclude multiple polyfills. These shorthands end with the plus sign (+).

polyfill(globalThis, {
	// disables polyfills for setTimeout clearTimeout
	exclude: 'Timeout+',
})

polyfill(globalThis, {
	// disables polyfills for Node, Window, Document, HTMLElement, etc.
	exclude: 'Node+',
})

polyfill(globalThis, {
	// disables polyfills for Event, EventTarget, Node, Window, Document, HTMLElement, etc.
	exclude: 'Event+',
})

Shorthand	Excludes
Document+	Document, HTMLDocument
Element+	Element, and exclusions from HTMLElement+
Event+	Event, CustomEvent, EventTarget, MediaQueryList, Window, and exclusions from Node+
EventTarget+	Event, CustomEvent, EventTarget, MediaQueryList, Window, and exclusions from Node+
HTMLElement+	CustomElementsRegistry, HTMLElement, HTMLBodyElement, HTMLCanvasElement, HTMLDivElement, HTMLHeadElement, HTMLHtmlElement, HTMLImageElement, HTMLStyleElement, HTMLTemplateElement, HTMLUnknownElement, Image
Node+	Node, DocumentFragment, ShadowRoot, Document, HTMLDocument, and exclusions from Element+
StyleSheet+	StyleSheet, CSSStyleSheet

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License & Attribution

Thank you to Jon Neal for his work on the original webapi project that this package is forked from. Licensed under the CC0-1.0 License.

Code from event-target-shim is licensed under the MIT License (MIT), Copyright Toru Nagashima.

Code from formdata-polyfill is licensed under the MIT License (MIT), Copyright Jimmy Wärting.