Exceptions in event handlers breaks further processing of event handlers #3580
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| @@ -248,7 +249,11 @@ export function on(elem, type, fn) { | |||
| if (event.isImmediatePropagationStopped()) { | |||
| break; | |||
| } else { | |||
| handlersCopy[m].call(elem, event, hash); | |||
| try { | |||
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this try/catch should probably be wrapped in an IIFE because try/catch
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That would make the code a lot uglier than it already is for little to no benefit. There should never be so many event handlers for any single event that the performance difference becomes an issue.
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I lean towards leaving this as-is.
added 2 commits
August 25, 2016 18:34
…ng further processing of event handlers
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| const el = document.createElement('div'); | ||
| const listener1 = function() { | ||
| throw new Error('GURU MEDITATION ERROR'); |
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LGTM |
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Description
In the event dispatch function, we do not guard against event handlers raising exceptions. If that happens, any further processing of event handlers and any code after the trigger stops as the exception continues to unwind the stack.
This is particularly problematic if the event was triggered by a source handler during the initialization stages of the handler. The SourceHandler can end up in a state from which it can not recover through no fault of our own.
See this example of a player broken by a simple exception thrown from an event handler:
http://jsbin.com/fipikerore/edit?html,output
Specific Changes proposed
Simply add a try/catch around each invocation of an event handler function called from the the
dispatchfunction.Requirements Checklist