对猫鼬模型的虚拟属性进行存根 [英] Stubbing virtual attributes of Mongoose model

问题描述

是否可以对猫鼬模型的虚拟属性进行存根?

Is there a way to stub a virtual attribute of a Mongoose Model?

假定Problem是模型类，并且difficulty是虚拟属性. delete Problem.prototype.difficulty返回false，并且该属性仍然存在，因此我无法将其替换为所需的任何值.

Assume Problem is a model class, and difficulty is a virtual attribute. delete Problem.prototype.difficulty returns false, and the attribute is still there, so I can't replace it with any value I want.

我也尝试过

var p = new Problem();
delete p.difficulty;
p.difficulty = Problem.INT_EASY;

那没有用.

将未定义的值分配给Problem.prototype.difficulty或使用sinon.stub(Problem.prototype, 'difficulty').returns(Problem.INT_EASY); 将在执行时抛出异常"TypeError:无法读取未定义的属性'scope'"

Assigning undefined to Problem.prototype.difficulty or using sinon.stub(Problem.prototype, 'difficulty').returns(Problem.INT_EASY); would throw an exception "TypeError: Cannot read property 'scope' of undefined", while doing

  var p = new Problem();
  sinon.stub(p, 'difficulty').returns(Problem.INT_EASY);

将引发错误"TypeError:尝试将字符串属性难度包装为函数".

would throw an error "TypeError: Attempted to wrap string property difficulty as function".

我的想法不多了.帮帮我！谢谢！

I am running out of ideas. Help me out! Thanks!

推荐答案

猫鼬删除它们，就不能重新配置.

mongoose internally uses Object.defineProperty for all properties. Since they are defined as non-configurable, you can't delete them, and you can't re-configure them, either.

但是，您可以做的是覆盖模型的get和set方法，这些方法用于获取和设置任何属性:

What you can do, though, is overwriting the model’s get and set methods, which are used to get and set any property:

var p = new Problem();
p.get = function (path, type) {
  if (path === 'difficulty') {
    return Problem.INT_EASY;
  }
  return Problem.prototype.get.apply(this, arguments);
};

或者，一个使用sinon.js的完整示例:

Or, a complete example using sinon.js:

var mongoose = require('mongoose');
var sinon = require('sinon');

var problemSchema = new mongoose.Schema({});
problemSchema.virtual('difficulty').get(function () {
  return Problem.INT_HARD;
});

var Problem = mongoose.model('Problem', problemSchema);
Problem.INT_EASY = 1;
Problem.INT_HARD = 2;

var p = new Problem();
console.log(p.difficulty);
sinon.stub(p, 'get').withArgs('difficulty').returns(Problem.INT_EASY);
console.log(p.difficulty);

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