本文实例讲述了nodejs nedb 封装库与使用方法。分享给大家供大家参考，具体如下：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);
}


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);
})();


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);
})();

执行命令
nodemon test.js


nodemon test.js

希望本文所述对大家node.js程序设计有所帮助。