Joi:自动验证函数参数 [英] Joi: Automatic validation of function arguments

问题描述

我看到一个使用 joi 库的代码库，如下所示:

I saw a codebase which was using joi library like this:

function f(a, b) {
  // ...
}

f.schema = {
  a: Joi.string().uuid().required(),
  b: Joi.number()
}

然后 f.schema 属性没有在其他任何地方被引用.是否有一些框架使用 schema 属性自动验证函数参数?谷歌搜索这没有提出任何东西.

And then the f.schema property wasn't referenced anywhere else. Is there some framework which performs automatic validation of function arguments using the schema property? Googling this didn't bring up anything.

推荐答案

我认为不可能完全按照您在此处显示的内容进行操作，因为 在 Javascript 中不可能重载函数调用，但有一种方法可以做一些非常相似的事情使用代理.

I don't think it is possible to do exactly what you are showing here, since overloading of function call is impossible in Javascript, but there is a way to do something pretty similar using Proxies.

这是我设法做到的.我们创建了一个 validated 代理对象，它覆盖了 apply 行为，它对应于标准函数调用，以及 apply 和 call 方法.

Here is what I've managed to do. We create a validated proxy object, that overrides the apply behavior, which corresponds to standard function calls, as well as apply and call methods.

代理检查函数上是否存在 schema 属性，然后使用 schema 数组的元素验证每个参数.

The proxy checks for the presence of a schema property on the function, then validates each argument using the elements of the schema array.

const Joi = require('joi');

const validated = function(f) {
    return new Proxy(f, {
        apply: function(target, thisArg, arguments) {
            if (target.schema) {
                for (let i = 0; i < target.length; i++) {
                    const res = target.schema[i].validate(arguments[i]);
                    if (res.error) {
                        throw res.error;
                    }
                }
            }
            target.apply(thisArg, arguments)
        }
    })
}

const myFunc = validated((a, b) => {
    console.log(a, b)
});

myFunc.schema = [
    Joi.string().required(),
    Joi.number(),
];

myFunc('a', 2);

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