* SUMMARY Very poor runtime error message dealing with undefined in strict mode compared to non-strict mode. * TEST <script> "use strict"; function Foo() { this._key = undefined; this._key.name = "test"; } new Foo; </script> * NON-STRICT (expected) [Error] TypeError: undefined is not an object (evaluating 'this._key.name = "test"') * STRICT (actual) [Error] TypeError: Attempted to assign to readonly property. * NOTES - Because Classes imply strict mode and we've started making heavy use of classes, this will greatly impact us when working on WebInspector.
This stumped me for a while today.
I'll take this