Create a Request, Stringify a Request into JSON, Hydrate JSON back into a Request

Request.js

// @ts-check

/** Creates a new Request. */
export const create = /** @type {(input: RequestInfo | URL, init?: RequestInit) => Request} */ (
	(input, config = any) => new Request(input, config)
)

/** Stringifies a Request into JSON. */
export const stringify = /** @type {(request: Request) => Promise<StringifiedRequest>} */ (async (request) => {
	/** URL of the request. */
	const input = request.url

	/** Configuration of the request. */
	const config = /** @type {StringifiedRequestConfig} */ ({})

	// assign any unique configuration from the request
	for (const name in defaultRequest) {
		if (request[name] !== defaultRequest[name]) {
			config[name] = request[name]
		}
	}

	// assign any headers from the request
	config.headers = Object.fromEntries(request.headers)

	// assign any body from the request
	if (!request.bodyUsed) {
		/** Blob retreived from the request. */
		const blob = await request.clone().blob()

		// serialize the type and array of the blob
		/** @type {[ string, number[] ]} */
		config.body = [
			blob.type,
			[
				...new Uint8Array(
					await blob.arrayBuffer()
				)
			]
		]
	}

	return [ input, config ]
})

/** Hydrates JSON back into a Request. */
export const hydrate = /** @type {(json: StringifiedRequest) => Request} */ (
	([ input, options ]) => new Request(
		input,
		{
			...options,
			body: options.body ? new Blob([
				new Uint8Array(options.body[1])
			], {
				type: options.body[0]
			}) : null,
		}
	)
)

const defaultRequest = {
	method: 'GET',
	referrer: 'about:client',
	/** @type {ReferrerPolicy} */
	referrerPolicy: '',
	/** @type {RequestMode} */
	mode: 'cors',
	/** @type {RequestCredentials} */
	credentials: 'same-origin',
	/** @type {RequestCache} */
	cache: 'default',
	/** @type {RequestRedirect} */
	redirect: 'follow',
	integrity: '',
	keepalive: false,
}

const any = /** @type {any} */ (null)

/** @typedef {typeof defaultRequest & { headers: { [name: string]: string }, body: [ string, number[] ] | null }} StringifiedRequestConfig */
/** @typedef {[ string, StringifiedRequestConfig ]} StringifiedRequest */