graphicek/client/src/api/request.ts

type RequestResult<
	T = void,
	TType extends 'json' | 'void' = 'json'
> = TType extends 'void' ? undefined : TType extends 'json' ? T : void

export class RequestError extends Error {
	constructor(public response: Response, message: string) {
		super(message)
	}
}

export class ResponseEmptyError extends RequestError {
	constructor(response: Response, message: string) {
		super(response, message)
	}
}

export const request = async <
	TResult = void,
	TType extends 'json' | 'void' = 'json'
>(
	url: string,
	options?: RequestInit,
	type?: TType
): Promise<RequestResult<TResult, TType>> => {
	const response = await fetch(url, options)

	if (!response.ok) {
		throw new RequestError(
			response,
			`${response.status} ${response.statusText}`
		)
	}

	if (type === 'void') {
		return undefined as RequestResult<TResult, TType>
	}

	const text = await response.text()

	if (!text) {
		if (!type || type === 'json') {
			throw new ResponseEmptyError(
				response,
				'Expected json, got empty response'
			)
		}

		return undefined as RequestResult<TResult, TType>
	}

	return JSON.parse(text) as RequestResult<TResult, TType>
}