lowdb - 간단한 DB 만들기

filesync는 fileasync도 아마 사용 가능한걸로 알고 있다.

정말 간단하게 구현해본 select, insert, update, delete

select와 insert에서 cond나 keys에다가 빼낼 필드 이름을 적어주면 그 필드들만 가져온다.

delete가 drop인건 delete가 예약어이기 때문.... 

var low = require('lowdb');
const FileSync = require('lowdb/adapters/FileSync')
const adapter = new FileSync(__dirname+'/../db/db.json')
const db = low(adapter)
/**
 * key
 * id  pw  name  birthday  sex  email  hp  favorites
 */
const defaultDataSet = {
    id: '',
    pw: '',
    name: '',
    birthday: '',
    sex: '',
    email: '',
    hp: '',
    favorites: []
}
db.defaults({ users: [{id:'test', pw:'123', name:'ktw'}] }).write();

/**
  * select * from users where id = key
  * ex) 
  * console.log(db.select('kwon3286'));
  * => { id: 'kwon3286', pw: 'asdf', name: 'asdf' }
  * 
  * @params { id, ['id', 'pw', ...] }
  * @returns { object{id:'', pw:'', name:'', ...} }
  */
const select = function(key, cond = []){
    const allInfo = db.get('users')
                    .find({id: key})
                    .value();
    if(cond.length === 0){
        return allInfo;
    }
    if(allInfo === undefined) return {};
    let result = {};
    for(let i=0;i<cond.length;i++){
        result[cond[i]] = allInfo[cond[i]];
    }
    return result;
}
  
 /**
  * insert
  */
const insert = function(value, keys = []){
    let info = {};
    info = JSON.parse(JSON.stringify(defaultDataSet));
  
    if(keys.length === 0){
        db.get('users')
        .push(value)
        .write()
    }else{
        for(let key of keys){
            info[key] = value[key];
        }
        db.get('users')
        .push(info)
        .write()
    }
 }
  
/**
  * update
  */
const update = function(id, key, value){
    let data = {};
    data[key] = value;
    db.get('users')
    .find({id: id})
    .assign(data)
    .write()
}
  
/**
 * drop
 */
const drop = function(id){
    db.get('users')
    .remove({ id: id })
    .write()
}
  
module.exports = {
    select,
    insert,
    update,
    drop,
}