timers: enable timers to be used as primitives

doc/api/timers.md

@@ -90,6 +90,12 @@ of the Node.js application.
 
 Returns a reference to the `Timeout`.
 
+### timeout[Symbol.toPrimitive]()
+
+When coercing a `Timeout` to a primitive, a primitive will be generated that can be used with the appropriate function that can be used to clear the `Timeout`. This allows enhanced compatibility with browser `setTimeout`, and `setInterval` implementations.
+
+Returns a `number`.
+
 ## Scheduling Timers
 
 A timer in Node.js is an internal construct that calls a given function after

lib/timers.js

@@ -504,7 +504,7 @@ exports.setInterval = function(callback, repeat, arg1, arg2, arg3) {
   return timeout;
 };
 
-exports.clearInterval = function(timer) {
+const clearInterval = exports.clearInterval = function(timer) {
   if (typeof timer === 'number' || typeof timer === 'string') {
     if (timer in KNOWN_TIMERS) {
       clearInterval(KNOWN_TIMERS[timer]);