javascript - bluebird promisify 函数未转换为 Promise

Question

他们还有其他方式进行 promise 转换吗？

var Promise = require("bluebird");
let findOneOrCreate = require('mongoose-find-one-or-create');
findOneOrCreate = Promise.promisify(findOneOrCreate); // not converted to promise

我在 .then() 中使用了类似的方法:-

        db.employee.findOneOrCreate({
                organization: model.organization.id,
                EmpDb_Emp_id: model.EmpDb_Emp_id
            }, model)
            .then((employee, created) => {
                if (!created) {
                    throw 'employee already exist';
                }
                return employee;
            }).catch(err => {
                throw err;
            });

它给出了一个错误:-

无法读取未定义的属性“then”

Answer 1

首先根据bluebird documentation ,

the node function should conform to node.js convention of accepting a callback as last argument

mongoose-find-one-or-create仅接受 schema 作为参数，并使用 findOneOrCreate 函数扩展此架构。所以看来 require('mongoose-find-one-or-create') 不能被 promise 。您可以尝试 promise 扩展模式的 findOneOrCreate:

var findOneOrCreate = require('mongoose-find-one-or-create');
var PersonSchema = mongoose.Schema({...});
PersonSchema.plugin(findOneOrCreate);
var Person = mongoose.model('Person', PersonSchema);
var findOneOrCreatePromise = Promise.promisify(Person.findOneOrCreate);

另请记住，Promise.promisify() 返回一个函数，因此您需要在调用 then 之前调用它:

findOneOrCreatePromise().then(...)

不只是

findOneOrCreatePromise.then(...)