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What’s the shortest syntax to check if jsonObject is not undefined before accessing its errorMessage property?
var jsonObject = SomeMethodReturningAnObject();
if (jsonObject.errorMessage === undefined) // jsonObject can be undefined and this will throw an error
/* success! */
else
alert(jsonObject.errorMessage);
You can use the
&&operator, since it doesn’t evaluate the right-hand side if the left-hand side isundefined: