Cacher is the code snippet organizer for pro developers

function main() {
  var db = new Kinto();
  
  // first collection
  var tasks = db.collection("tasks");
  tasks.events.on('change', function(event) {
    console.log('changed in tasks');
  })
  
  // second collection
  var second = db.collection("second");
  second.events.on('change', function(event) {
    console.log('changed in second');
  })
  
  // notice in the console, the event handler fires for both collection, even though only "tasks" has changed
  
  var syncOptions = {
    remote: "https://kinto.dev.mozaws.net/v1/",
    headers: {Authorization: "Basic " + btoa("user:pass")}
  };
  document.getElementById("form")
    .addEventListener("submit", function(event) {
      event.preventDefault();
      tasks.create({
        title: event.target.title.value,
        done: false
      })
      .then(function(res) {
        event.target.title.value = "";
        event.target.title.focus();
      })
      .then(render)
      .catch(function(err) {
        console.error(err);
      });
    });

  document.getElementById("clearCompleted")
    .addEventListener("click", function(event) {
      event.preventDefault();
      tasks.list()
        .then(function(res) {
          var completed = res.data.filter(function(task) {
            return task.done;
          });
          return Promise.all(completed.map(function(task) {
            return tasks.delete(task.id);
          }));
        })
        .then(render)
        .catch(function(err) {
          console.error(err);
        });
    });

  function doSync() {
    return tasks.sync(syncOptions).catch(function(err) {
      if (err.message.includes("flushed")) {
        console.warn("Flushed server detected, marking local data for reupload.");
        return tasks.resetSyncStatus()
          .then(function() {
            return tasks.sync(syncOptions);
          });
      }
      throw err;
    });
  }

  function handleConflicts(conflicts) {
    return Promise.all(conflicts.map(function(conflict) {
      return tasks.resolve(conflict, conflict.remote);
    }))
      .then(doSync);
  }

  document.getElementById("sync")
    .addEventListener("click", function(event) {
      event.preventDefault();
      doSync()
        .then(function(res) {
          document.getElementById("results").value = JSON.stringify(res, null, 2);
          if (res.conflicts.length) {
            return handleConflicts(res.conflicts);
          }
          return res;
        })
        .then(render)
        .catch(function(err) {
          console.error(err);
        });
    });

  function renderTask(task) {
    var tpl = document.getElementById("task-tpl");
    var li = tpl.content.cloneNode(true);
    li.querySelector(".title").textContent = task.title;
    li.querySelector(".uuid").textContent = task.id;
    // retrieve a reference to the checkbox element
    var checkbox = li.querySelector(".done");
    // initialize it with task status
    checkbox.checked = task.done;
    // listen to cliecks
    checkbox.addEventListener("click", function(event) {
      // prevent the click to actually toggle the checkbox
      event.preventDefault();
      // invert the task status
      task.done = !task.done;
      // update task status
      tasks.update(task)
        .then(render)
        .catch(function(err) {
          console.error(err);
        });
    });
    return li;
  }

  function renderTasks(tasks) {
    var ul = document.getElementById("tasks");
    ul.innerHTML = "";
    tasks.forEach(function(task) {
      ul.appendChild(renderTask(task));
    });
  }

  function render() {
    tasks.list().then(function(res) {
      renderTasks(res.data);
    }).catch(function(err) {
      console.error(err);
    });
  }

  render();
}

window.addEventListener("DOMContentLoaded", main);