Join在数组中验证Sum

Question

我想验证给定的JSON，约束为expenditure不能超过credit

{
"expenditure": {
"house": 2,
"electricity": 1,
"phone": 12
},
"credit": 6
}

const Joi = require("joi");
const schema = Joi.object({
expenditure: Joi.object({
house: Joi.number().integer().min(0).max(5).optional(),
electricity: Joi.number().integer().min(0).max(5).optional(),
phone: Joi.number().integer().min(0).max(5).optional()
}),
credit: Joi.number().integer().min(0).max(15).greater(
Joi.ref('expenditure', {"adjust": expenditure => {
return expenditure.house + expenditure.electricity + expenditure.phone;
}})
)
});

上面的代码适用于在对象范围内进行约束，但我需要对进行验证

[
{
"phone_allowance": 12
},
{
"phone_allowance": 10
},
]

为了确保阵列中所有phone_allowance的总和永远不会超过某个给定值，例如50

Answer 1

您可以使用custom()

https://github.com/sideway/joi/blob/master/API.md#anycustommethod-描述

工作演示

var schema = Joi.array().items(
Joi.object({
phone_allowance: Joi.number()
})
).custom((value, helpers) => {
var total = value.reduce((a, b) => a + b.phone_allowance, 0)
if (total > 5) {
return helpers.error('any.invalid');
}
return value;
});