query: how to determine if variable is undefined
positive_passages.docid: 37735
positive_passages.text: How can I check for "undefined" in JavaScript?
negative_passages.docid: 83782
negative_passages.text: How to check a not-defined variable in JavaScript
negative_passages.docid: 50773
negative_passages.text: How to determine the type of a variable in Swift
negative_passages.docid: 105287
negative_passages.text: (Why) is using an uninitialized variable undefined behavior?
negative_passages.docid: 126341
negative_passages.text: Avoiding IF ELSE due to variable been NULL
negative_passages.docid: 25999
negative_passages.text: How is the return status of a variable assignment determined?
negative_passages.docid: 86651
negative_passages.text: How to determine if Javascript object is an event?
negative_passages.docid: 27212
negative_passages.text: Variables might not have been initialized
negative_passages.docid: 96061
negative_passages.text: Console returns undefined
negative_passages.docid: 32293
negative_passages.text: What's the difference between if(!$variable) and if(isset($variable))?
negative_passages.docid: 113018
negative_passages.text: Javascript shorthand if
negative_passages.docid: 19252
negative_passages.text: Determine original name of variable after its passed to a function
negative_passages.docid: 109927
negative_passages.text: JavaScript null check
negative_passages.docid: 141197
negative_passages.text: In JavaScript, is there an easier way to check if a property of a property exists?
negative_passages.docid: 5307
negative_passages.text: Check if a variable is in an ad-hoc list of values
negative_passages.docid: 5451
negative_passages.text: How do I check if an element is hidden in jQuery?
negative_passages.docid: 103811
negative_passages.text: Can I determine if an argument is string literal?