[英]Lodash using curry with bind cause a typescript error
I'm trying to use the bind
method with curry
, but it gives me a type error.我正在尝试将bind
方法与curry
一起使用,但它给了我一个类型错误。
const curried = curry(this.method.bind(this));
const getSomething = curried(a, b);
Getting TS error from getSomething:从 getSomething 获取 TS 错误:
expected 0-1 arguments but got 2.预期 0-1 个参数,但得到 2 个。
When I am not using the bind method it's not complaining.当我不使用 bind 方法时,它不会抱怨。
const curried = curry(this.method);
const getSomething = curried(a, b);
The problem is that this is the signature of bind:问题是这是 bind 的签名:
bind(this: Function, thisArg: any, ...argArray: any[]): any;
So the return of bind
for a function is any
, curry
still works because any
can be converted to any other type, so the first overload in declaration order of curry
is used namely this one:所以函数bind
的返回值是any
, curry
仍然有效,因为any
可以转换为任何其他类型,所以使用curry
声明顺序中的第一个重载,即这个:
curry<T1, R>(func: (t1: T1) => R, arity?: number): CurriedFunction1<T1, R>;
With T1
and R
being inferred to {}
. T1
和R
被推断为{}
。
This is a reason to stay away from bind
, it loses type info.这是远离bind
一个原因,它会丢失类型信息。 It is difficult to write a general type safe version of bind
, since it can bind both this
and function arguments, but a version that just binds this
and preserves type info in easy to write:很难编写一个通用类型安全的bind
版本,因为它可以绑定this
和函数参数,但是一个只绑定this
并保留类型信息的版本很容易编写:
function typedThisBind<T1, T2, T3, T4, R>(fn: (t: T1, t2: T2, t3: T3, t4 : T4) => R, thisArg: any) : typeof fn
function typedThisBind<T1, T2, T3, R>(fn: (t: T1, t2: T2, t3: T3) => R, thisArg: any) : typeof fn
function typedThisBind<T1, T2, R>(fn: (t: T1, t2: T2) => R, thisArg: any) : typeof fn
function typedThisBind<T1, R>(fn: (t: T1) => R, thisArg: any) : typeof fn
function typedThisBind<R>(fn: () => R, thisArg: any) : () => R
function typedThisBind(fn: Function, thisArg: any) : any {
return fn.bind(thisArg);
}
Now using this version of bind all should work as expected (for functions with up to 5 arguments, but you can easily add more):现在使用这个版本的 bind all 应该可以按预期工作(对于最多有 5 个参数的函数,但您可以轻松添加更多):
class Foo {
method(a: number, b: number) {}
m(){
const curried = curry(typedThisBind(this.method, this));
const getSomething = curried(0, 0); // Works as expected.
}
}
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