Augments all methods on a given object to log a message to the console when called.

logMethodCalls.js

/**
 * Augments all methods on a given object to log a message to the console when called.
 * Useful for understanding how objects are used during an application's lifecycle.
 *
 * @param  {string} baseName   Logged as the indentifer before called method names.
 * @param  {object} target     The object with methods that should be monitored for calls.
 *
 * @return {object} Returns the modified target object.
 */
function logMethodCalls(baseName, target) {
	for (const key of Object.keys(target)) {
		const value = target[key];
		// We only care about function properties...
		if (typeof value === 'function') {
			// Create a new function to replace the original method, that behaves identitically to the original function
			// except it logs a message to the console when called.
			function logger(...args) {
				console.log(
					`%cMETHOD CALL%c ${baseName}.${key}()`,
					'color: #fff; background-color: #07C; padding: 1px 6px; border-radius: 2px',
					'color: #07C;'
				);
				// Ensure the correct `this` value and all arguments are pass through to original function.
				// Also ensure our wrapper returns any value returned by the original function.
				return value.apply(this, args);
			}
			// Make this wrapper function obvious in call stacks.
			logger.name = `logger(${value.name})`;
			target[key] = logger;
		}
	}

	return target;
}