renovate/lib/util/decorator/index.ts

64 lines
1.4 KiB
TypeScript

export type Handler<T> = (
parameters: DecoratorParameters<T>,
) => Promise<unknown>;
export type Method<T> = (this: T, ...args: any[]) => Promise<any>;
export type Decorator<T> = <U extends T>(
target: U,
key: keyof U,
descriptor: TypedPropertyDescriptor<Method<T>>,
) => TypedPropertyDescriptor<Method<T>>;
export interface DecoratorParameters<T, U extends any[] = any[]> {
/**
* Current call arguments.
*/
args: U;
/**
* A callback to call the decorated method with the current arguments.
*/
callback(this: void): unknown;
/**
* Current call context.
*/
instance: T;
/**
* The decorated method name.
*/
methodName?: string;
}
/**
* Applies decorating function to intercept decorated method calls.
* @param fn - The decorating function.
*/
export function decorate<T>(fn: Handler<T>): Decorator<T> {
const result: Decorator<T> = (
target,
key,
descriptor = {
enumerable: true,
configurable: true,
writable: true,
...Object.getOwnPropertyDescriptor(target, key),
},
) => {
const { value } = descriptor;
return Object.assign(descriptor, {
value(this: T, ...args: any[]) {
return fn({
args,
instance: this,
callback: () => value?.apply(this, args),
methodName: value?.name,
});
},
});
};
return result;
}