Typescript 函数重载,参数问题
在此代码中,声明了几个重载函数:Typescript 函数重载,参数问题,typescript,overloading,Typescript,Overloading,在此代码中,声明了几个重载函数: export function rect(a: Point, b: Point): Rect; export function rect(a: Point, b: number|Point, c?: number): Rect; export function rect(a: number|Point, b: number|Point, c?: number, d?: number ) {return new Rect(a,b,c,d);} rect( 1,1,
export function rect(a: Point, b: Point): Rect;
export function rect(a: Point, b: number|Point, c?: number): Rect;
export function rect(a: number|Point, b: number|Point, c?: number, d?: number ) {return new Rect(a,b,c,d);}
rect( 1,1,1, 1) // ts: "Expected 2-3 arguments, but got 4.ts(2554)"
Typescript在第4个参数中抱怨。我不知道这里出了什么问题。如果我再添加一个重载和一个参数:
export function rect(a: Point, b: Point): Rect;
export function rect(a: Point, b: number|Point, c?: number): Rect;
export function rect(a: number|Point, b: number|Point, c?: number, d?: number ): Rect ;
export function rect(a: number|Point, b: number|Point, c?: number, d?: number, e?: number ): Rect {return new Rect(a,b,c,d);}
rect( 1,1,1, 1)
ts没有抱怨(如果我将第5个参数添加到对rect的调用中,它会给出相同的错误)
怎么了?最后一个重载签名是实现签名,外部不可见。如果要使该接口公开,则需要复制该接口:
export function rect(a: Point, b: Point): Rect;
export function rect(a: Point, b: number | Point, c?: number): Rect;
export function rect(a: number | Point, b: number | Point, c?: number, d?: number): Rect;
export function rect(a: number | Point, b: number | Point, c?: number, d?: number) {
return new Rect(a, b, c, d);
}
函数实现必须满足所有重载拒绝。如果需要更多参数,请添加另一个重载