Sync Function
The sync function can be used to bridge async functions with traditional
continuation-passing style (CPS) functions. Use the sync function to create
a callback with an associated Promise which can be used as a deferred result
for the callback.
Example
const fs = require("fs");
const sync = require("sync");
async function asyncReadFile(file) {
const done = sync(); // create synchronization primitive
fs.readFile(file, done); // pass primitive as CPS callback
return done.promise; // return resulting promise
}