使用Mongoose模型静态的Promises

Question

I have a piece of code which finds the record with the highest value for a Numeric field, 'ordinal':

Job.find({}).sort({'ordinal': -1}).limit(1).then(maxOrd => {
    console.log(`Found MaxOrd: ${maxOrd}`);
});

This works fine. Now I'd like to make this a static method of the Job schema. As so I tried:

JobSchema.statics.findMaxOrdinal = function(callback) {
    Job.find({}, callback).sort({'ordinal': -1}).limit(1);

};

...and:

Job.findMaxOrdinal().then(maxOrd => {
    console.log(`Found Max Ord using Promise: ${maxOrd}`);
});

But this isn't working, and crashes with a very unhelpful stack trace.

How do I write my static so that I can use it with a Promise?

Answer 1

Just return mongoose query like this:

JobSchema.statics.findMaxOrdinal = function() {
    return Job.find({}).sort({'ordinal': -1}).limit(1);
};