sveltekit-superfetch

SvelteKit libary for interacting with APIs with support for optional logging of requests and responses

Usage

Usage is similar to using the standard fetch API. No options are required. The fetcher will default to a timeout of 8 seconds and 3 retries if no values for those options are specified.

(The examples below work with v2.0.0 and above.)

Creating a New Instance

This is often best done in a lib that creates a singleton that can be imported as needed elsewhere in your project. If you just want to use the defaults for all options, you can do:

lib/superfetch.ts

import { SuperFetch } from 'sveltekit-superfetch'
export default const superFetch = new SuperFetch() 

You can also customize the fetcher. Example options:

lib/superfetch.ts

import { SuperFetch } from 'sveltekit-superfetch'
export default const superFetch = new SuperFetch({
   retry: 3,
   timeout: 8000, // 8 seconds
   ttl: 1000, // 1 second. Max age of cached responses.  Only individual queries with a 'key' specified in the options will be cached.
   logger: logger, // injected logger instance, default is `console`, must implement info() and error()
   logFormat: 'json', // text or json, default is json
   logLevel: 'verbose' | 'limited' | 'silent', // default is 'limited' in dev mode, 'silent' in prod
   excludedPaths: ['/api/auth'], // an array of strings, fetches to routes containing these strings will not be logged
   limitedPaths: ['/'] // an array of strings, log entries will not contain headers, bodies, cookies, or url params
})

Using the root path ('/') in the array of limitedPaths will make all log entries contain only limited information. This could be useful if you need to trace an error, but your data is sensitive.

Example fetch with POST method, headers, and body

import superFetch from '$lib/superFetch'
const response = await superFetch.query({
   url: 'https://example.org', 
   method: 'POST',
   headers: {
      'Content-Type': 'application/json'
   },
   body: JSON.stringify({ key: 'value' })
   // ...any other properties supported in basic fetch request
   // see https://developer.mozilla.org/en-US/docs/Web/API/fetch
})

Example fetch that will be cached server-side with optional ttl override

import superFetch from '$lib/superFetch'
const response = await superFetch.query({
   url: 'https://example.org/api/product', 
   key: 'products',
   ttl: 10000 // 10 seconds
})

Even a cache with a relatively short ttl, such as 1 second, can provide a large performance boost and reduce hits to third-party APIs on high-traffic sites. Do not attempt to cache request types other than GET. Do not cache sensitive or dynamic endpoints, such as customer profiles.

Basic example with no options

import superFetch from '$lib/superFetch'
const response = await superFetch.query("https://example.org")

If you create a new instance of SuperFetch without passing in a logger instance, it will use console (console.log() and console.error()) by default.