TypeScript decorator with arguments example

decorator_with_arguments.ts

function logClass(target:any, filterName?:string):any {
	var original = target;

	function construct(constructor, args) {
		let c:any = function () {
			return constructor.apply(this, args);
		};
		c.prototype = constructor.prototype;
		return new c;
	}

	let f:any = (...args) => {

		// Filter by Name patch
		/////////////////////////////////////
		if (filterName == args[0]+args[1]) {
			console.log(`Detected new amazing person: ${original.name}(${JSON.stringify(args)})`);
		}
		else {
			console.log(`Create new: ${original.name}(${JSON.stringify(args)})`);
		}
		//////////////////////////////////////

		return construct(original, args);
	};

	f.prototype = original.prototype;
	return f;
}



function logFilter(filter) {

	let name = filter.when.name + filter.when.surname;

	return (target:any) => {
		return logClass(target, name);
	}
}



@logFilter({
	when: {
		name: 'Super',
		surname: 'Man'
	}
})
class Person {
	constructor(
		public name:string,
		public surname:string
	){}
}

let person1 = new Person("Alex", "Mayorov");
let person2 = new Person("Super", "Man");

/* Out:

Create new Person(["Alex","Mayorov"])
Detected new amazing Person(["Super","Man"])

*/