优雅的方式来增加一个mongoose数字字段

什么是最优雅的方式来增加一个mongoose数字的字段？

var Book = new Schema({ name: String, total: Number }) 

我如何在API中增加它？

 var book = new Book({ name: req.body.name, total: ? }); book.save(callback); 

Answer 1

您可以编写一个mongoose插件，拦截保存调用并从计数器集合中返回当前计数器。

mongoose插件

 var mongoose = require('mongoose'); var Schema = mongoose.Schema; module.exports = function(schema, options) { var options = options || {}; options.name = options.name || 'generic'; options.field = options.field || 'counter'; var counterSchema = new Schema({ name : String, counter : Number }); var CounterModel = mongoose.model('counters', counterSchema); schema.pre('save', function (next) { if (!this.isNew) { return next(); } var self = this; CounterModel.findOneAndUpdate( { name : options.name }, { $inc : { counter : 1 } }, { upsert : true }, function(err, counter) { if (err) { return next(err) }; self.set(options.field, counter.counter); next(); }); }); } 

这个插件知道在名为counters的集合中保留多个命名的counters 。

使用mongoose插件

 var mongoose = require('mongoose'); var Schema = mongoose.Schema; var counter = require('./plugin'); var TestSchema = new Schema({ counter : Number }); TestSchema.plugin(counter, { name : 'tests', counter : 'counter' }); var TestModel = mongoose.model('tests', TestSchema); mongoose.connect('mongodb://localhost', function(err) { TestModel.create({}, function(err, test) { console.log(err, test); test.save(function(err, test) { console.log(err, test); }); }); });