问题描述
假设您要跟踪一个或多个唯一标识符。在这种情况下,next.config.js
const withImages = require('next-images')
module.exports = withImages()
具有两个对于A
唯一的属性,而A
仅具有一个对B
唯一的属性。
B
如果只有一个唯一键,我们可以执行以下操作:
protocol HavingUID {
// Some way to use KeyPath?
}
struct A : HavingUID {
var unique1 : String
var unique2 : Int
}
struct B : HavingUID {
var unique1 : Double
}
let a1 = A(unique1:"val",unique2: 1)
let a2 = A(unique1:"val",unique2: 2)
let b1 = B(unique1:0.5)
let b2 = B(unique1:0.0)
let b3 = B(unique1:0.2)
let arrA : [HavingUID] = [a1,a2]
let arrB : [HavingUID] = [b1,b2,b3]
// How to check arrA and arrB for duplicate UID properties?
...但是那限制了我一键。
解决方法
每当您需要使用唯一标识符时,绝对应该使用全局结构或枚举来跟踪它们。这是两种简单的方法:
结构:
struct UniqueIdentifiers {
static let id1 = "identifier_one"
static let id2 = "identifier_two"
static let id3 = "identifier_three"
}
let currentID = UniqueIdentifiers.id1
枚举:
enum UniqueIdentifiers: String {
case id1 = "identifier_one"
case id2 = "identifier_two"
case id3 = "identifier_three"
}
let currentID = UniqueIdentifiers.id1.rawValue