process: support symbol events

Event emitters support symbols as event names. The process object assumes that the event name is a string, and examines the first three characters to check for signals. This causes an exception if the event name is a symbol. This commit ensures that the event name is a string before trying to slice() it. PR-URL: #4798 Reviewed-By: Sam Roberts <[email protected]> Reviewed-By: Michaël Zasso <[email protected]> Reviewed-By: Wyatt Preul <[email protected]>

Author: cjihrig

src/node.js

@@ -819,7 +819,8 @@
 varsignalWraps={};
 
 functionisSignal(event){
-returnevent.slice(0,3)==='SIG'&&
+returntypeofevent==='string'&&
+event.slice(0,3)==='SIG'&&
 startup.lazyConstants().hasOwnProperty(event);
 }
 

test/parallel/test-process-emit.js

@@ -0,0 +1,20 @@
+'use strict';
+constcommon=require('../common');
+constassert=require('assert');
+constsym=Symbol();
+
+process.on('normal',common.mustCall(data=>{
+assert.strictEqual(data,'normalData');
+}));
+
+process.on(sym,common.mustCall(data=>{
+assert.strictEqual(data,'symbolData');
+}));
+
+process.on('SIGPIPE',common.mustCall(data=>{
+assert.strictEqual(data,'signalData');
+}));
+
+process.emit('normal','normalData');
+process.emit(sym,'symbolData');
+process.emit('SIGPIPE','signalData');