async-ready allows you to register async dependencies and be alerted when all of them are ready.
npm install async-ready
Pass the module a promise which will be resolved once your dependency is ready.
Say you don't want your server to start listening for connections until a long-running call has completed as part of start-up.
const asyncReady = require('async-ready');
// register this async dependency as not yet ready (as soon as it's loaded into memory)
asyncReady.registerDependency( new Promise( (resolve) => {
// perform long-running operation
thisTakesSomeTime()
// resolve the promise to alert anyone listening that this dependency is ready
.then( () => resolve() );
}));const asyncReady = require('async-ready');
// wait until all async dependencies are loaded before listening for connections
asyncReady.onDependenciesReady().then( () => {
server.listen(8080);
});You can track as many dependencies as you want. Just register them normally as shown in the example above.