@toss/nestjs-aop/esm/create-decorator.js

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import { applyDecorators } from '@nestjs/common';
import { AddMetadata } from './utils';
/**
 * @param metadataKey equal to 1st argument of Aspect Decorator
 * @param metadata The value corresponding to the metadata of WrapParams. It can be obtained from LazyDecorator's warp method and used.
 */
export const createDecorator = (metadataKey, metadata) => {
    const aopSymbol = Symbol('AOP_DECORATOR');
    return applyDecorators(
    // 1. Add metadata to the method
    (target, propertyKey, descriptor) => {
        return AddMetadata(metadataKey, {
            originalFn: descriptor.value,
            metadata,
            aopSymbol,
        })(target, propertyKey, descriptor);
    }, 
    // 2. Wrap the method before the lazy decorator is executed
    (_, propertyKey, descriptor) => {
        const originalFn = descriptor.value;
        descriptor.value = function (...args) {
            var _a;
            const wrappedFn = (_a = this[aopSymbol]) === null || _a === void 0 ? void 0 : _a[propertyKey];
            if (wrappedFn) {
                // If there is a wrapper stored in the method, use it
                return wrappedFn.apply(this, args);
            }
            // if there is no wrapper that comes out of method, call originalFn
            return originalFn.apply(this, args);
        };
        /**
         * There are codes that using `function.name`.
         * Therefore the codes below are necessary.
         *
         * ex) @nestjs/swagger
         */
        Object.defineProperty(descriptor.value, 'name', {
            value: propertyKey.toString(),
            writable: false,
        });
        Object.setPrototypeOf(descriptor.value, originalFn);
    });
};
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