在 Sequelize 的交易中使用循环和承诺

你应该使用Promise.all

    var members = req.body.members;
    models.sequelize.transaction(function (t) {
        var promises = []
        for (var i = 0; i < members.length; i++) {
            var newPromise = models.User.create({'firstname':members[i], 'email':members[i], 'pending':true}, {transaction: t});
           promises.push(newPromise);
        };
        return Promise.all(promises).then(function(users) {
            var userPromises = [];
            for (var i = 0; i < users.length; i++) {
                userPromises.push(users[i].addInvitations([group], {transaction: t});
            }
            return Promise.all(userPromises);
        });
    }).then(function (result) {
        console.log("YAY");
    }).catch(function (err) {
        console.log("NO!!!");
        return next(err);
    });

我不认为你需要在续集交易中catch，因为我认为它会跳到交易的陷阱中

抱歉格式化。在移动设备上。

Promise.all 将在运行 .then 之前等待所有承诺返回（或失败），.then回调将是每个数组中的所有 promise 数据

你需要使用蓝鸟的内置循环结构，它附带续集：

    var members = req.body.members;
    models.sequelize.transaction(t => 
      Promise.map(members, m => // create all users
        models.User.create({firstname: m, email: m, 'pending':true}, {transaction: t})
      ).map(user => // then for each user add the invitation
         user.addInvitations([group], {transaction: t}) // add invitations
    )).nodeify(next); // convert to node err-back syntax for express

根据您对 Node 的实现.js这可能会有所帮助。我使用express，POSTGRES和sequelize进行了相同的设置。

就个人而言，我更喜欢 async/await （ES6） 实现而不是 then/catch，因为它更容易阅读。此外，创建一个可以在外部调用的函数可以提高可重用性。

async function createMemeber(req) {
let members = req.body.members;
  for (var i = 0; i < members.length; i++) {
    // Must be defined inside loop but outside the try to reset for each new member;
    let transaction = models.sequelize.transaction();
    try { 
      // Start transaction block.
      let user = await models.User.create({'firstname':members[i],  'email':members[i], 'pending':true}, {transaction});
      await user.addInvitations([group], {transaction}));
      // if successful commit the record. Else in the catch block rollback the record.
      transaction.commit();
      // End transaction block.
      return user;
    } catch (error) { 
      console.log("An unexpected error occurred creating user record: ", error);
      transaction.rollback();
      // Throw the error back to the caller and handle it there. i.e. the called express route.
      throw error;
    }
  }
}

如果有人正在寻找使用异步和等待的打字稿v4.0.5的解决方案，那么这里对我来说就是可行的。也许你也可以在你的javascript应用程序上使用它，但它取决于它的版本。

const array = ['one','two','three'];
const createdTransaction = sequelize.transaction();
    
const promises = array.map(async item => {
      await model.create({
          name: item,
      },
      { transaction: createdTransaction },
     );
});
Promise.all(promises).then(async values => {
    await createdTransaction.commit();
});

第一：https://caolan.github.io/async/docs.html

因此，很容易：

// requiring...
const async = require('async');
// exports...
createAllAsync: (array, transaction) => {
  return new Promise((resolve, reject) => {
    var results = [];
    async.forEachOf(array, (elem, index, callback) => {
      results.push(models.Model.create(elem, {transaction}));
      callback();
    }, err => {
      if (err) {
        reject(err);
      }
      else {
        resolve(results);
      }
    });
  });
}