Koa2学习之旅----mongodb数据库查询分页信息

db.表名.find().skip((page-1)*pageSize).limit(pageSize)

db.collection(collectionName).find(json1,{fields:attr}).skip(slipNum).limit(pageSize);

    find (collectionName, json1, json2, json3) {
        if (arguments.length == 2) {
            var attr = {};
            var slipNum = 0;
            var pageSize = 0;

        } else if (arguments.length == 3) {
            var attr = json2;
            var slipNum = 0;
            var pageSize = 0;
        } else if (arguments.length == 4) {
            var attr = json2;
            var page = json3.page || 1;
            var pageSize = json3.pageSize || 20;
            var slipNum = (page - 1) * pageSize;
        } else {
            console.log('传入的参数错误')
        }

        return new Promise((resolve, reject) => {

            this.connect().then((db) => {
                //var result=db.collection(collectionName).find(json);
                var result = db.collection(collectionName).find(json1, { fields: attr }).skip(slipNum).limit(pageSize);
                result.toArray(function (err, docs) {

                    if (err) {
                        reject(err);
                        return;
                    }
                    resolve(docs);
                })

            })
        })
    }