nodejs - nedb 封装库-白红宇

nodejs - nedb 封装库

阅读量：6242 次

发布时间：2019-06-22

本文共 2620 字，大约阅读时间需要 8 分钟。

libs/nedb.js

const Datastore = require('nedb');function DB(database) {    let options = {        filename: database,        autoload: true,    };    this.db = new Datastore(options);}DB.prototype.limit = function(offset, limit) {    this.offset = offset || 0;    this.limit = limit || 15;    return this;}DB.prototype.sort = function(orderby) {    this.orderby = orderby;    return this;}DB.prototype.find = function(query, select) {    return new Promise((resolve, reject) => {        let stmt = this.db.find(query || {});        if (this.orderby !== undefined) {            stmt.sort(this.orderby);        }        if (this.offset !== undefined) {            stmt.skip(this.offset).limit(this.limit);        }        if (select != undefined) {            stmt.projection(select || {});        }        stmt.exec((err, docs) => {            if (err) {                return reject(err);            }            resolve(docs);        })    })};DB.prototype.findOne = function(query, select) {    return new Promise((resolve, reject) => {        let stmt = this.db.findOne(query || {});        if (this.sort !== undefined) {            stmt.sort(this.sort);        }        if (select != undefined) {            stmt.projection(select || {});        }        stmt.exec((err, doc) => {            if (err) {                return reject(err);            }            resolve(doc);        })    })}DB.prototype.insert = function(values) {    return new Promise((resolve, reject) => {        this.db.insert(values, (err, newDoc) => {            if (err) {                return reject(err);            }            resolve(newDoc);        })    })}DB.prototype.update = function(query, values, options) {    return new Promise((resolve, reject) => {        this.db.update(query || {}, values || {}, options || {}, (err, numAffected) => {            if (err) {                return reject(err);            }            resolve(numAffected);        })    });}DB.prototype.remove = function(query, options) {    return new Promise((resolve, reject) => {        this.db.remove(query || {}, options || {}, (err, numAffected) => {            if (err) {                return reject(err);            }            resolve(numAffected);        })    });}module.exports = (database) => {    return new DB(database);}

test.js

const db = require('./libs/nedb')('testdb');(async function() {	await db.insert({number: 12});	await db.insert({number: 11});	await db.insert({number: 13});	let res = await db.sort({number: -1}).limit(0, 2).find();	console.log(res);})();

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