async-lib-pattern

async-lib-pattern.js

var libPromise = new Promise(function(resolve) {
  window.Lib =  window.Lib || [];
  window.Lib.push(resolve);
});

libPromise.then(function(lib) {
  // ...
});

libPromise.then(function(lib) {
  // ...
});


// Also works:
window.Lib =  window.Lib || [];
window.Lib.push(function(lib) {
 // ...
});

// Lib implementation
const clients = Array.isArray(window.Lib) ? window.Lib : [];
window.Lib = {
  version: '1.0',
  push(cb) {
    cb(this);
  }
};
clients.forEach(cb => cb(window.Lib));