Description

Hooks for use class metadata in method or property decorator

Installation

npm install --save metadata-hooks

Usage

Create class decorator for defining scope in class metadata

// scope.decorator.ts

import { setClassMetadata } from 'metadata-hooks';

function Scope(scope: string): ClassDecorator {
    return setClassMetadata('scope', scope);
}

export { Scope };

Create method decorator using class metadata for saving method names unique per scope

// method.decorator.ts

import { useClassMetadata } from 'metadata-hooks';

const usedMethods = new Map <string, Set <string>> ();

function Method(): MethodDecorator {
    return useClassMetadata('scope', (scope: string) => {
        const scopeMethods = usedMethods.get(scope) ?? new Set();

        if (!usedMethods.has(scope)) {
            usedMethods.set(scope, scopeMethods);
        }

        return (prototype: Prototype, methodName: string) => {
            if (scopeMethods.has(methodName)) {
                throw new Error(`Method '${methodName}' is already used in scope '${scope}'`);
            }

            Reflect.defineMetadata('methodName', `${scope}:${methodName}`, prototype, methodName);

            scopeMethods.add(methodName);
        };
    });
}

export { Method };

Use decorators @Scope() and @Method()

// main.ts

import { Scope } from './scope.decorator';
import { Method } from './method.decorator';

@Scope('company')
class UserController {
    @Method() // <-- Ok
    public createCompany(name: string): Company {
        // ...
    }

    @Method() // <-- Ok
    public getCompanies(): Company[] {
        // ...
    }
}

@Scope('company')
class AdminController {
    @Method() // <-- Error
              // Method 'getCompanies' is already used in scope 'company'
    public getCompanies(): Company[] {
        // ...
    }
}

License

MIT