TypeScript：不能将“new”与类型缺少调用或构造签名的表达式一起使用
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TypeScript: Cannot use 'new' with an expression whose type lacks a call or construct signature
提问by alekop
I have a function that instantiates a object with a given constructor, passing along any arguments.
我有一个函数，它使用给定的构造函数实例化一个对象，传递任何参数。
function instantiate(ctor:Function):any {
switch (arguments.length) {
case 1:
return new ctor();
case 2:
return new ctor(arguments[1]);
case 3:
return new ctor(arguments[1], arguments[2]);
...
default:
throw new Error('"instantiate" called with too many arguments.');
}
}
It is used like this:
它是这样使用的：
export class Thing {
constructor() { ... }
}
var thing = instantiate(Thing);
This works, but the compiler complains about each new ctorinstance, saying Cannot use 'new' with an expression whose type lacks a call or construct signature.. What type should ctorhave?
这有效，但编译器抱怨每个new ctor实例，说Cannot use 'new' with an expression whose type lacks a call or construct signature.. 应该ctor有什么类型？
回答by Ryan Cavanaugh
I'd write it this way (with generics as a bonus):
我会这样写（使用泛型作为奖励）：
function instantiate<T>(ctor: { new(...args: any[]): T }): T {
回答by John Zabroski
I also got this error when my type was wrapped in a module, and I was calling new on the module rather than the type. This Q&A helped me rule out some things, and then I came to the realization it was something quite silly after a long day of programming.
当我的类型被包装在一个模块中时，我也遇到了这个错误，我在模块上调用了 new 而不是类型。这个问答帮助我排除了一些事情，然后我意识到在经过一整天的编程之后这很愚蠢。
