node.js - 一段js代码的简写问题

Question

    options.filename = dbPath+'picker';
    pickerDB = new Datastore(options);
    options.filename = dbPath+'data';
    dataDB = new Datastore(options);
    options.filename = dbPath+'web';
    webDB = new Datastore(options);
    options.filename = dbPath+'url';
    urlDB = new Datastore(options);
    options.filename = dbPath+'attach';
    attachDB = new Datastore(options);
    options.filename = dbPath+'cacheUrl';
    cacheUrlDB = new Datastore(options);
    options.filename = dbPath+'cache';
    cacheDB = new Datastore(options);
    options.filename = dbPath+'cron';
    cronDB = new Datastore(options);
    options.filename = dbPath+'log';
    logDB = new Datastore(options);
    options.filename = dbPath+'cronLog';
    cronLogDB = new Datastore(options);

请教一下，这一大段，都是复制粘贴。能用更简洁的代码一次搞定吗？

Answer 1

不知道算不算你心中的简写，我觉得从重复的角度看，把不同的部分提取出来做个数组，把相同的部分抽象，如下：

let options = {},
    dbPath = ''; //TBD by yourself

let stores = [
    'picker',
    'data',
    'web',
    'url',
    'attach',
    'cacheUrl',
    'cache',
    'cron',
    'log',
    'cronLog']
    .map(key => (options.filename = dbPath + key, new Datastore(options)));


console.log(stores); //stores you want

Answer 2

    /*
        options == ?
        dbPath == ?
    */
    var _Datastore = {};
    _Datastore._opts = options;
    _Datastore._path = dbPath;
    _Datastore.Create = function(pathAddon){
        this._opts.filename = this._path + pathAddon;
        return new Datastore(this.options);
    };
    
    pickerDB = _Datastore.Create('picker');
    dataDB = _Datastore.Create('data');
    webDB = _Datastore.Create('web');
    urlDB = _Datastore.Create('url');
    attachDB = _Datastore.Create('attach');
    cacheUrlDB = _Datastore.Create('cacheUrl');
    cacheDB = _Datastore.Create('cache');
    cronDB = _Datastore.Create('cron');
    logDB = _Datastore.Create('log');
    cronLogDB = _Datastore.Create('cronLog');

不知道你接下来的代码怎么用？如果后边的逻辑代码好改，可以改成：

    var _Datastore = {};
    _Datastore._opts = options;
    _Datastore._path = dbPath;
    _Datastore._cache = {};
    _Datastore.Create = function(pathAddon){
        this._opts.filename = this._path + pathAddon;
        return new Datastore(this.options);
    };
    _Datastore.DB = function(pathAddon){
        this._cache[pathAddon] = this._cache[pathAddon] || this.Create(pathAddon);
        return this._cache[pathAddon];
    };

    
    //调用 cronLogDB 时 改成 
    _Datastore.DB('cronLog');
    
    //第一次 会创建，第二次直接用之前创建的实例