Calling the returned function signals to run the specified function or, if the function is already executing, flag that it should run once more.

onceMore.js

function onceMore(f) {

    var isWorking = false,
        isWaiting = false;

    function execute() {
        isWaiting = false;
        isWorking = true;
        f().then(complete);
    }

    function complete() {
        if (isWaiting) {
            execute();
        } else {
            isWorking = false;
        }
    }

    function queue() {
        if (isWorking) {
            isWaiting = true;
        } else {
            execute();
        }
    };

    return queue;
}

Example Usage

var doStuff = function(){
  return new Promise(function executor(resolve, reject){
    setTimeout(function(){
      // Simulate long running async task
      resolve();
    }, 10000);
  });
}

var doStuffOnceMore = onceMore(doStuff);

doStuffOnceMore();
doStuffOnceMore();
doStuffOnceMore();
doStuffOnceMore();