ES6 同步執行任意多個Promise

核心代碼

var taskIndex = 0;
var taskFinishIndex = 0;

function addSyncTask(func, resolve, reject) {
  var taskId = taskIndex;
  taskIndex++;

  function callback() {
    if (taskId == taskFinishIndex) {
      new Promise(func).then(function (data) {
        resolve(data);
        taskFinishIndex++;
      }).catch(function (err) {
        reject(err);
        taskFinishIndex++;
      });
    } else {
      setTimeout(callback, 100);
    }
  }

  setTimeout(callback, 100);
}

使用Demo

addSyncTask(function (resolve, reject) {
	  console.log("task_0 start!");
  setTimeout(function () {
    try {
      resolve();
    } catch (err) {
      reject(err);
    }
  }, 3000);
}, function (data) {
  console.log("task_0 end!");
});

addSyncTask(function (resolve, reject) {
  setTimeout(function () {
    try {
      console.log("task_1 start!");
      resolve();
    } catch (err) {
      reject(err);
    }
  }, 100);
}, function (data) {
  console.log("task_1 end!");
});

addSyncTask(function (resolve, reject) {
  setTimeout(function () {
    try {
      console.log("task_2 start!");
      resolve();
    } catch (err) {
      reject(err);
    }
  }, 100);
}, function (data) {
  console.log("task_2 end!");
});

運行結果

task_0 start!
task_0 end!
task_1 start!
task_1 end!
task_2 start!
task_2 end!