Method call log with experimental Typescript decorators

index.ts

const DEBUG = false;

const logDebug = function(_target: any, key: string, descriptor: PropertyDescriptor): any {
    const originalMethod = descriptor.value;
    descriptor.value = function(...args: any[]) {
        const functionName = key;
        console.log(functionName + "(" + args.join(", ") + ")");
        const result = originalMethod.apply(this, args);
        console.log("=> " + result);
        return result;
    };
    return descriptor;
};
const logNoop = function() {};
const log = DEBUG ? logDebug : logNoop;

class Test {
    @log
    test(a: number, b: number) {
    }
}

new Test().test(1, 2);
new Test().test(3, 5);