diff --git a/lib/events.js b/lib/events.js index d676580df3..da2dc599ca 100644 --- a/lib/events.js +++ b/lib/events.js @@ -257,8 +257,9 @@ function _addListener(target, type, listener, prepend) { if (m && m > 0 && existing.length > m) { existing.warned = true; const w = new Error('Possible EventEmitter memory leak detected. ' + - `${existing.length} ${type} listeners added. ` + - 'Use emitter.setMaxListeners() to increase limit'); + `${existing.length} ${String(type)} listeners ` + + 'added. Use emitter.setMaxListeners() to ' + + 'increase limit'); w.name = 'MaxListenersExceededWarning'; w.emitter = target; w.type = type; diff --git a/test/parallel/test-event-emitter-check-listener-leaks.js b/test/parallel/test-event-emitter-check-listener-leaks.js index 1e357cd027..18d2d065b8 100644 --- a/test/parallel/test-event-emitter-check-listener-leaks.js +++ b/test/parallel/test-event-emitter-check-listener-leaks.js @@ -1,7 +1,7 @@ 'use strict'; require('../common'); -var assert = require('assert'); -var events = require('events'); +const assert = require('assert'); +const events = require('events'); var e = new events.EventEmitter(); @@ -13,6 +13,14 @@ assert.ok(!e._events['default'].hasOwnProperty('warned')); e.on('default', function() {}); assert.ok(e._events['default'].warned); +// symbol +const symbol = Symbol('symbol'); +e.setMaxListeners(1); +e.on(symbol, function() {}); +assert.ok(!e._events[symbol].hasOwnProperty('warned')); +e.on(symbol, function() {}); +assert.ok(e._events[symbol].hasOwnProperty('warned')); + // specific e.setMaxListeners(5); for (let i = 0; i < 5; i++) { diff --git a/test/parallel/test-event-emitter-max-listeners-warning-for-null.js b/test/parallel/test-event-emitter-max-listeners-warning-for-null.js new file mode 100644 index 0000000000..3a31150657 --- /dev/null +++ b/test/parallel/test-event-emitter-max-listeners-warning-for-null.js @@ -0,0 +1,22 @@ +// Flags: --no-warnings +// The flag suppresses stderr output but the warning event will still emit +'use strict'; + +const common = require('../common'); +const events = require('events'); +const assert = require('assert'); + +const e = new events.EventEmitter(); +e.setMaxListeners(1); + +process.on('warning', common.mustCall((warning) => { + assert.ok(warning instanceof Error); + assert.strictEqual(warning.name, 'MaxListenersExceededWarning'); + assert.strictEqual(warning.emitter, e); + assert.strictEqual(warning.count, 2); + assert.strictEqual(warning.type, null); + assert.ok(warning.message.includes('2 null listeners added.')); +})); + +e.on(null, function() {}); +e.on(null, function() {}); diff --git a/test/parallel/test-event-emitter-max-listeners-warning-for-symbol.js b/test/parallel/test-event-emitter-max-listeners-warning-for-symbol.js new file mode 100644 index 0000000000..fc0a3dba0e --- /dev/null +++ b/test/parallel/test-event-emitter-max-listeners-warning-for-symbol.js @@ -0,0 +1,24 @@ +// Flags: --no-warnings +// The flag suppresses stderr output but the warning event will still emit +'use strict'; + +const common = require('../common'); +const events = require('events'); +const assert = require('assert'); + +const symbol = Symbol('symbol'); + +const e = new events.EventEmitter(); +e.setMaxListeners(1); + +process.on('warning', common.mustCall((warning) => { + assert.ok(warning instanceof Error); + assert.strictEqual(warning.name, 'MaxListenersExceededWarning'); + assert.strictEqual(warning.emitter, e); + assert.strictEqual(warning.count, 2); + assert.strictEqual(warning.type, symbol); + assert.ok(warning.message.includes('2 Symbol(symbol) listeners added.')); +})); + +e.on(symbol, function() {}); +e.on(symbol, function() {}); diff --git a/test/parallel/test-event-emitter-max-listeners-warning.js b/test/parallel/test-event-emitter-max-listeners-warning.js index 717315cf63..168ed02f19 100644 --- a/test/parallel/test-event-emitter-max-listeners-warning.js +++ b/test/parallel/test-event-emitter-max-listeners-warning.js @@ -15,6 +15,7 @@ process.on('warning', common.mustCall((warning) => { assert.strictEqual(warning.emitter, e); assert.strictEqual(warning.count, 2); assert.strictEqual(warning.type, 'event-type'); + assert.ok(warning.message.includes('2 event-type listeners added.')); })); e.on('event-type', function() {});