Nodejs ORM2callback参数

我在for语句中创build模型：

for (var j = 0; j < data.length; j++) { models.MyModel1.create({ name : data[j].name }, function(err, model){ if (err) { throw err } models.OtherMyModel.create({ model_id : model.id, index : j }], function(err,submodule){ }); }); } 

所以在这里我想创build将使用父模型id和它的索引j的子模型。 而因为asynchronousvar j将data.length – 1的所有callback。 我怎样才能将索引parameter passing给模型创buildcallback？

Answer 1

你可以使用promise来实现。
以下代码片段在以下情况下使用：

 var when = require('when'); var nodefn = require('when/node/function'); var promises = []; // Wrap model creation functions by a promise var createMyModel1 = nodefn.lift(models.MyModel1.create); var createOtherMyModel = nodefn.lift(models.OtherMyModel.create); for (var j = 0; j < data.length; j++) { // Store the index into a local variable because when the first promise // will resolve, `i` would be equal to `data.length`! var index = j; // Create the first model var promise = createMyModel1({ name: data[j].name }).then(function(model) { // Once the model is created, create the submodel return createOtherMyModel({ model_id: model.id, index: index }); }, function(err) { throw err; }); // Store the promise in order to synchronize it with the others promises.push(promise); } // Wait for all promises to be resolved when.all(promises).then(function() { console.log('All models are created'); }); 

另一个解决scheme是使用yield和任何协程运行程序（自node.js 0.11.x起可用）：

 var co = require('co'); // Thunkify model creation functions var createMyModel1 = function(data) { return function(fn) { models.MyModel1.create(data, fn); }; }; var createOtherMyModel = function(data) { return function(fn) { models.OtherMyModel.create(data, fn); }; }; co(function *() { for (var j = 0; j < data.length; j++) { // Create first model var model = yield createMyModel1({ name: data[j].name }); // Create its submodel var submodel = yield createOtherMyModel({ model_id: model.id, index: j }); } })();