Method _applyMixin

framework/framework/server.ts:864–887

(Target: any, MixinClass: Partial<any> | ((t: Partial<any>) => Partial<any>))

    }

    private _applyMixin(Target: any, MixinClass: Partial<any> | ((t: Partial<any>) => Partial<any>)) {
        if (!('prototype' in Target)) throw new Error('Target must be a class.');
        if (typeof MixinClass === 'function') MixinClass = MixinClass(Target.prototype);
        this.ctx.effect(() => {
            let oldValue = null;
            for (const val of Object.getOwnPropertyNames(MixinClass)) {
                if (Target.prototype[val]) {
                    logger.warn(`${Target.name}.prototype[${val}] already exists.`);
                    oldValue = Target.prototype[val];
                }
                Target.prototype[val] = MixinClass[val];
            }
            return () => {
                for (const val of Object.getOwnPropertyNames(MixinClass)) {
                    if (Target.prototype[val] !== MixinClass[val]) {
                        logger.warn(`Failed to unload mixin ${Target.name}.prototype[${val}]: not the same as the original value.`);
                    } else {
                        delete Target.prototype[val];
                        if (oldValue) Target.prototype[val] = oldValue;
                    }
                }
            };
        });
    }

    public applyMixin<T extends keyof KnownHandlers>(name: T, MixinClass: any) {
        this.withHandlerClass(name, (HandlerClass) => {