Contain async insanity so that the dark pony lord doesn't eat souls
See this blog post.
Pass a callback to dezalgo
and it will ensure that it is always called in a future tick, and never in this tick.
var dz = require('dezalgo') var cache = {} function maybeSync(arg, cb) { cb = dz(cb) // this will actually defer to nextTick if (cache[arg]) cb(null, cache[arg]) fs.readFile(arg, function (er, data) { // since this is *already* defered, it will call immediately if (er) cb(er) cb(null, cache[arg] = data) }) }