YAFA

YAFA (Yet Another Fetch alternative) is a super simple library that allow to "wrap" fetch requests and responses.

Request wrappers

const requestWrapper = (delegate, url, ...rest) => {
  return delegate(`${url}-wrapped`, ...rest)
}
 
const wrappedFetch = fetch.wrapRequest(requestWrapper)
 
// fetch will be called with 'http://some-url-wrapped'
// as first argument
wrappedFetch('http://some-url')

A request wrapper takes every arguments given to fetch call, preceded by a callback function (named delegate in the above example). This callback function should be called as if it was the real fetch function (i.e. with modified parameters).

const requestWrapper = (delegate, url, ...rest) => {
  return delegate(`${url}-wrapped`, ...rest)
}
 
const anotherRequestWrapper = (delegate, url, ...rest) => {
  return delegate(`${url}-wrappedAnotherTime`, ...rest)
}
 
// fetch will be called with
// 'http://some-url-wrapped-wrappedAnotherTime'
// as first argument
const wrappedFetch = fetch.wrapRequest(requestWrapper)
                          .wrapRequest(anotherRequestWrapper)
 
 
wrappedFetch('http://some-url')

Response wrappers

const responseWrapper = response => response.replace.split('e').join('a')
 
const newFetch = fetch.wrapResponse(responseWrapper)
 
// Every occurrence of 'e' has been replace
// by a 'a' in the response
newFetch().then(response => console.log(response))

In response wrapper, the modified response should be returned by the wrapper.

As request wrappers, response wrappers can be chained.

const responseWrapper = response => response.replace.split('e').join('a')
const responseWrapper2 = response => response.replace.split('a').join('i')
 
const newFetch = fetch.wrapResponse(responseWrapper)
                      .wrapResponse(responseWrapper2)
 
// Every occurrence of 'e' and 'a' has been replace
// by a 'i' in the response
newFetch().then(response => console.log(response))