src/taskqueue.js

export default TaskQueue;

function TaskQueue() {
  this.isReady = false;
  this.failed = false;
  this.queue = [];
}

TaskQueue.prototype.execute = function () {
  var fun;
  if (this.failed) {
    while ((fun = this.queue.shift())) {
      fun(this.failed);
    }
  } else {
    while ((fun = this.queue.shift())) {
      fun();
    }
  }
};

TaskQueue.prototype.fail = function (err) {
  this.failed = err;
  this.execute();
};

TaskQueue.prototype.ready = function (db) {
  this.isReady = true;
  this.db = db;
  this.execute();
};

TaskQueue.prototype.addTask = function (fun) {
  this.queue.push(fun);
  if (this.failed) {
    this.execute();
  }
};