Mongoose實現虛擬字段查詢的方法詳解

var hooks = require('hooks')
 , Document = require('./path/to/some/document/constructor');
// Add hooks' methods: `hook`, `pre`, and `post`
for (var k in hooks) {
 Document[k] = hooks[k];
}
// Define a new method that is able to invoke pre and post middleware
Document.hook('save', Document.prototype.save);

// 上述代碼在mongoose中實現
/////////////////////////////////////////////////////////////////////
// 下面的代碼則是mongoose提供的Hook API

// Define a middleware function to be invoked before 'save'
Document.pre('save', function validate(next) {
 // ...
});

// 設置 findOne 和 find 鉤子
CompanySchema.pre('findOne', preFind).pre('find', preFind);

function preFind() {
 var word = this.getQuery().word;
 if(word === undefined) return;

 // 從真實的Query中刪掉虛擬屬性
 delete this._conditions.word;
 // 構造正則表達式
 var regex = new RegExp(word);
 // 全文檢索
 this.where({ $or: [{ title: regex }, { content: regex }, { author: regex }] });
}