typescript 合并两个接口
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Merge Two Interfaces
提问by Estus Flask
Seeking confirmation or clarification
寻求确认或澄清
If I have two interfaces. What is the "proper" way to create a merge of those two interfaces.
如果我有两个接口。创建这两个接口的合并的“正确”方法是什么。
Foo
富
IFoo{
// some stuff
}
Bar
酒吧
IBar{
// some stuff
}
IFooBar
IFooBar
IFooBar extends IFoo, IBar{
// Empty
}
It works but it feels weird, like I am doing it wrong with the empty IFooBar.
它有效，但感觉很奇怪，就像我对空的 IFooBar 做错了一样。
Am I doing this correctly?
我这样做正确吗？
I also noticed that this also works:
我还注意到这也有效：
type IFooBar = IFoo & IBar;
I have an illogical aversion to using typeyet, it is much cleaner.
我对使用有一种不合逻辑的厌恶type，它更干净。
回答by Estus Flask
This articleexplains the relation between interfaces and type aliases very well, this partis focused on small differences between them.
这篇文章很好地解释了接口和类型别名之间的关系，这部分主要关注它们之间的细微差别。
Both
两个都
interface IFooBar extends IFoo, IBar {}
and
和
type IFooBar = IFoo & IBar;
are common ways to do this and will behave identically in most cases. Since typetakes less characters to type, it could be chosen for that reason.
是执行此操作的常用方法，并且在大多数情况下表现相同。由于type需要较少的字符来键入，因此可以选择它。
The inconsistency that is caused by mixed interfaceand typeshouldn't be a problem; they are just suitable features to achieve the goal. If const BarClass = FooClassdoes the job, class BarClass extends FooClass {}shouldn't be preferred just because its consistently uses classeverywhere (this example is used for illustrative purposes, there's a considerable difference between these approaches).
由混合引起的不一致性interface和type不应该是一个问题; 它们只是实现目标的合适特征。如果可以const BarClass = FooClass完成这项工作，则class BarClass extends FooClass {}不应仅仅因为它始终class在任何地方使用而成为首选（此示例用于说明目的，这些方法之间存在相当大的差异）。
Even though interfaceand typecan behave similarly, there is a difference in case of merged interface (also covered in linked article). This will work:
尽管interface和type行为相似，但合并界面的情况有所不同（也在链接文章中介绍）。这将起作用：
interface FooBar extends IFoo, IBar {}
class FooBar { ... }
And this will cause type error:
这将导致类型错误：
type FooBar = IFoo & IBar;
class FooBar { ... }
回答by Stephen Paul
If you're wanting to merge 2 interfaces which contain members more than 1 level deep:
如果您想合并包含深度超过 1 级的成员的 2 个接口：
export interface TypeOne {
one: {
two: {
hello: string;
}[]
}
}
export type TypeTwo = {
one: {
two: {
world: string;
}[]
}
} & TypeOne;
const x: TypeTwo;
x.one.two[0]. // autocompletes options are 'hello' / 'world'
回答by Pavel
I think there it is ok, or not ok relating to what meaning of the merged interface. If IFooBaris a new entity from perspective of object-oriented design, then empty interface is all right. But if there is no such entity, but you want just merge some unrelated interfaces (for some hacky code) - then just use IFoo & IBarin variable type definition, or typefor shortening this.
我认为这与合并接口的含义无关。如果IFooBar是面向对象设计的新实体，那么空接口也可以。但是，如果没有这样的实体，但您只想合并一些不相关的接口（对于某些 hacky 代码） - 那么只需IFoo & IBar在变量类型定义中使用，或者type缩短它。
It's just my opinion as programmer, that came from object oriented languages like C++ and C#.
这只是我作为程序员的看法，来自 C++ 和 C# 等面向对象的语言。
