One promise for multiple requests in flight to avoid async duplication
const inflight = require('promise-inflight')
// some request that does some stuff
function req(key) {
// key is any random string. like a url or filename or whatever.
return inflight(key, () => {
// this is where you'd fetch the url or whatever
return Promise.delay(100)
})
}
// only assigns a single setTimeout
// when it dings, all thens get called with the same result. (There's only
// one underlying promise.)
req('foo').then(…)
req('foo').then(…)
req('foo').then(…)
req('foo').then(…)
Tests!