Dezalgo is a popular npm package designed to contain async insanity and prevent the so-called "dark pony lord" from consuming souls. On a more technical level, dezalgo ensures that a provided callback function is always called in a future tick, thereby handling asynchronous actions effectively. It provides a guarantee that whenever a callback is passed through it, the callback will not execute synchronously but will always wait to execute until the next process tick, thus preventing inconsistencies from synchronous callback invocations.
To use dezalgo in your JavaScript project, first, you will need to install it using npm by running npm install dezalgo
. Next, you will require it in your file with var dz = require('dezalgo')
. You should then pass your callback function to dezalgo to ensure it is called in the next process tick. Here's a brief example:
var dz = require('dezalgo')
var cache = {}
function maybeSync(arg, cb) {
cb = dz(cb)
if (cache[arg]) cb(null, cache[arg]) // if the result is cached, defer the callback to the next tick
fs.readFile(arg, function (er, data) {
if (er) cb(er)
cb(null, cache[arg] = data) // call the callback immediately since it's already deferred
})
}
In this code, maybeSync
function reads a file asynchronously using fs.readFile
, and if an error occurs, it invokes the callback with the error. But if it doesn't, it stores the file data in a cache
object and calls the callback function.
The documentation for the Dezalgo npm package can be found directly in the readme file within the package's repository on GitHub. The link to access this documentation is https://github.com/npm/dezalgo. Take note that this documentation includes a usage section, which provides valuable insights into how to best utilize the dezalgo package in your JavaScript applications.