async-ready

async-ready allows you to register async dependencies and be alerted when all of them are ready.

Installation

npm install async-ready

Usage

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.

someDependency.js

 
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() );
 
    }));
 

app.js

 
const asyncReady = require('async-ready');
 
// wait until all async dependencies are loaded before listening for connections
asyncReady.onDependenciesReady().then( () => {
 
  server.listen(8080);
 
});
 

Multiple dependencies

You can track as many dependencies as you want. Just register them normally as shown in the example above.