javascript-sdk/Request.ts

import fetch from 'isomorphic-unfetch'

export default class RequestWrapper {
	private static cache: Array<Request<any>> = []

	public static getRequest<T>(url: string) {
		let req = this.cache.find((req) => req.url === url) as Request<T>|undefined
		if (!req) {
			req = new Request<T>(url)
			this.cache.push(req)
		}
		return req
	}
}

export class Request<T = any> {
	public static ttl = 1000 * 60 * 60 // 1 hour
	private response?: T
	private fetched?: Date
	public url: string // url is public for quick url test

	public constructor(url: string) {
		this.url = url
	}

	public async get(): Promise<T> {
		const now = new Date()
		if (
			this.fetched &&
			this.response &&
			now.getTime() - this.fetched.getTime() < Request.ttl
		) {
			return this.response
		}

		// Fetch Response
		try {
			const resp = await fetch(this.url, {
				headers: {
					"Content-Type": "text/plain"	
				}
			})
			if (resp.status !== 200) {
				throw new Error(`Error request ended with the code (${resp.status})`)
			}
			const response = await resp.json()
			this.response = response
			this.fetched = now
			return response
		} catch (e) {
			console.error(e)
			throw new Error('An error occured')
		}
	}
}