spy.ts

spy.ts

import {inspect} from 'util';

/**
 * This show arguments and output of a function / a method
 *
 * @param {Function} thisArg
 * @param {Function} func
 */
export const spy = <T, A extends any[], R, F extends (this: T, ...args: A) => R>(thisArg: T, func: F): F => {
    return function() {
        console.debug(inspect(arguments));
        const res = func.apply(thisArg, arguments as any);
        console.debug(inspect(res));
        return res;
    } as F;
}