Typescript 函数采用一个或一组对象
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Typescript function taking one or array of objects
提问by Tomas
We are using simple function declaration quite a lot where function takes either single object or array of objects of some type.
我们经常使用简单的函数声明，其中函数接受单个对象或某种类型的对象数组。
Simple declaration is:
简单的声明是：
interface ISomeInterface {
name: string;
}
class SomeClass {
public names: ISomeInterface[] = [];
public addNames(names: ISomeInterface | ISomeInterface[]): void {
names = (!Array.isArray(names)) ? [names] : names;
this.names = this.names.concat(names);
}
}
But TypeScript throws "type is not assignable" error.
但是 TypeScript 会抛出“类型不可分配”错误。
Is there better way of doing this? Obviously we could have two separate functions, but I think handling single vs multiple this way is quite fine.
有没有更好的方法来做到这一点？显然我们可以有两个独立的函数，但我认为以这种方式处理单个和多个函数非常好。
回答by isvforall
You can make it easier
你可以让它更容易
addNames(names: ISomeInterface | ISomeInterface[]): void {
this.names = this.names.concat(names);
}
From MDN
来自MDN
The concat() method returns a new array comprised of the array on which it is called joined with the array(s) and/or value(s)provided as arguments.
concat() 方法返回一个新数组，该数组由调用它的数组与作为参数提供的数组和/或值连接而成。
回答by Silvermind
You could also use the rest parameter:
您还可以使用 rest 参数：
interface ISomeInterface {
name: string;
}
class SomeClass {
public names: ISomeInterface[] = []; // create an instance if applicable.
addNames(...names: ISomeInterface[]): void {
// the names argument will always be an array
this.names = this.names.concat(names);
}
}
You can call it like:
你可以这样称呼它：
addNames(name1); // just pass one
addNames(name1, name2, name3); // pass more comma separated
addNames(...[name1, name2, name3]); // pass an array.
Please note that I removed the functionkeyword, because otherwise the thiskeyword inside the body block might lose scope depending on who's calling it.
请注意，我删除了function关键字，否则thisbody 块内的关键字可能会失去作用域，具体取决于调用它的人。
回答by Martin
I think this is what you want
我想这就是你想要的
interface ISomeInterface {
name: string;
}
class SomeClass {
public names: ISomeInterface[];
addNames(names: ISomeInterface | ISomeInterface[]): void {
names = (names instanceof Array) ? names : [names];
this.names = this.names.concat(<ISomeInterface[]>names)
}
}
You want to use instanceOf, not isArray.
您想使用instanceOf，而不是 isArray。
回答by Marie
The official way typescript handles this is with multiple function signatures, for example:
官方的打字稿处理方式是使用多个函数签名，例如：
addNames(names: ISomeInterface): void;
addNames(names: ISomeInterface[]): void;
addNames(names: any): void {
...
}
You can see more information in the official handbook here
您可以在此处查看官方手册中的更多信息
