如何使用 Joi 根据计算值验证对象？

Question

我在 wgich 中有一个对象，我想用一些计算值来验证它的值。现在我正在使用 javascript 方式进行操作，但我想使用 Joi 来进行操作。

{
    "scoreThreshold": 1,
    "questions": [
      {
        "question": "someString",
        "answer": 1,
        "factor": 2
      },
      {
        "question": "someString"
        "answer": 3
      },
      {
        "question": "someString",
        "answer": 0,
        "factor": 3
      },
      {
        "question": "someString"
        "answer": 1
      }
    ],
  }

我正在使用 javascript 验证它

var validator = function(doc) {
    var maxScore = 0
    for (var item of doc.questions) {
        maxScore += 1000 * (item.factor == undefined ? 1: item.factor)
    }

    if (maxScore == 0) {
        throw new Error("maxScore is 0")
    }

    if (doc.scoreThreshold > maxScore) {
        throw new Error("scoreThreshold more than maxScore")
    } else if ((doc.scoreThreshold / maxScore) > 0.95) {
        throw new Error("scoreThreshold too close to maxScore")
    }
}

如何以Joi 方式进行此验证？

Answer 1

我们可以使用Joi.ref() 的adjust 选项以Joi 方式执行此操作

var calculateMaxScore = function(questions) {
    return (questions || []).reduce((t, e) => t + 1000 * (e.factor == undefined ? 1: e.factor), 0)
}

var schema = Joi.object({
    "scoreThreshold": Joi.number().integer()
        .greater(0)
        .less(Joi.ref('questions', { adjust: (v) => calculateMaxScore(v) * 0.95 }))
        .required(),    
    "questions": Joi.array().items(Joi.object({
        "question": JJoi.string().min(1)).required(),
        "answer": Joi.number().integer().min(0).required(),
        "factor": Joi.number().integer().min(0)
    }))
    .required()
})

Answer 2

您可以使用any.custom() 进行自定义验证

any.custom(method, [description])

var schema = Joi.object()
  .keys({
    scoreThreshold: Joi.number(),
    questions: Joi.array().items(
      Joi.object({
        question: Joi.string(),
        answer: Joi.number(),
        factor: Joi.number()
      })
    )
  })
  .custom((doc, helpers) => {
    var maxScore = 0;
    for (var item of doc.questions) {
      maxScore += 1000 * (item.factor == undefined ? 1 : item.factor);
    }

    if (maxScore == 0) {
      throw new Error("maxScore is 0");
    }

    if (doc.scoreThreshold > maxScore) {
      throw new Error("scoreThreshold more than maxScore");
    } else if (doc.scoreThreshold / maxScore > 0.95) {
      throw new Error("scoreThreshold too close to maxScore");
    }

    // Return the value unchanged
    return doc;
  });

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