在我的一些个人项目中,我试图设计几种对象和列表类型。这些对象和列表应该是可序列化的(即具有toJSON()
和fromJSON()
方法)。一个示例对象和列表将具有以下基本代码:
type IPerson = {
id: number;
name: string;
// additional properties
}
class Person {
id: number;
name: string;
// additional properties
constructor(id: number, name: string, ...) { ... }
toJSON(): IPerson { return { ... } }
static fromJSON(json: IPerson): Person { return new Person(...) }
// additional methods
}
class PersonList {
list: Person[];
constructor(list: Person[]) { ... }
findById(id: number) { return this.list.find(it => it.id === id) }
findByName(name: string) { return this.list.find(it => it.name === name) }
add(person: Person) { this.list.push(person) }
remove(person: Person) { this.list = this.list.filter(it => it !== person) }
toJSON(): IPerson[] { return this.list.map(it => it.toJSON()) }
static fromJSON(json: IPerson[]): PersonList { return new PersonList(json.map(it => Person.fromJSON(it))) }
// additional methods
}
我正在处理的所有对象和列表都至少有此处列出的方法。
现在,我正在尝试将其转换为通用解决方案,使得:
type JSON = {
id: number;
name: string;
}
abstract class BaseObject<T extends JSON> {
abstract get id();
abstract get name();
constructor(id: number, name: string) { ... }
abstract toJSON(): T
abstract static fromJSON(json: T): BaseObject<T>
}
class BaseList<T, U> {
list: BaseObject<T>[];
constructor(list: BaseObject<T>[]) { ... }
findById(id: number) { return this.list.find(it => it.id === id) }
findByName(name: string) { return this.list.find(it => it.name === name) }
add(obj: BaseObject<T>) { this.list.push(obj) }
remove(obj: BaseObject<T>) { this.list = this.list.filter(it => it !== obj) }
toJSON(): U[] { return this.list.map(it => it.toJSON()) }
static fromJSON(json: U[]): BaseList<T, U> { return new BaseList<T, U>(json.map(it => BaseObject<T>.fromJSON(it))) }
}
如果这个结构起作用的话(但实际上它并没有),那么我的生活就会变得像这样简单:
type IPerson = JSON & {
// additional fields
}
class Person extends BaseObject<IPerson> {
get id() { ... }
get name() { ... }
// additional getters for other fields
toJSON(): IPerson { return { ... } }
static fromJSON(json: IPerson): Person { return new Person(...) }
// additional methods
}
class PersonList extends BaseList<Person, IPerson> {
// additional methods
}
// other object and list types definitions follow
然而,我的解决方案在以下几个点上失败:
BaseObject
不能有抽象静态的fromJSON()
方法。BaseList
不能有抽象静态的fromJSON()
方法。BaseList.fromJSON()
不能实例化新的列表,也不能调用BaseObject.fromJSON()
实例化新对象。