MongoDB $rename javascript 变量的键名 [英] MongoDB $rename javascript variable for key name

问题描述

各位，我正在尝试使用 $rename 运算符 (http://docs.mongodb.org/manual/reference/operator/update/rename/)

Folks, I am trying to use the $rename operator (http://docs.mongodb.org/manual/reference/operator/update/rename/)

作品:

collection.update( {_id: id}, {$rename: {'foo': 'bar'} } , function (err, result) {});

不会:

var this = 'foo';
var that = 'bar';
collection.update( {_id: id}, {$rename: {this: that} } , function (err, result) {});

为什么不允许我在 mongoclient 中使用变量来指定事物?

Why am I not allowed to use variables in the mongoclient to specify things?

谢谢

推荐答案

试试这个:

var this = 'foo';
var that = 'bar';
var rename_query = {'$rename': {}};
rename_query['$rename'][this] = that;
collection.update( {_id: id}, rename_query , function (err, result) {});

问题在于对象构造函数{foo:bar}，key隐含了像{'foo':bar}这样的引号，所以不可能在那里使用一个变量.但是您可以像在我的代码示例中一样单独构建对象.

The issue is that the object constructor {foo: bar}, the key implies the quotation marks like {'foo': bar} so it is not possible to use a variable there. But you can build the object separately like in my code example.

另外，请注意变量 this 是一个特殊的关键字.不要使用 this 作为常规变量名.语法高亮甚至有不同的颜色！请使用其他名称.

Also, beware that the variable this is a special keyword. Do not use this as a regular variable name. The syntax highlighting even has it in a different color! Please use a different name.

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