COMPUTER PROGRAMMING FUNDAMENTALS
WHAT IS PROGRAMMING
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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What does JavaScript return to you if you try to access a object’s property that doesn’t exist?
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null
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undefined
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‘oopsies!’
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0
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Explanation:
Detailed explanation-1: -JavaScript will return ‘undefined’ if we try to access properties or call methods that do not exist in the given object.
Detailed explanation-2: -If a property does not exist in the object, it returns false . Unlike the hasOwnProperty() method, the in operator looks for the property in both own properties and inherited properties of the object.
Detailed explanation-3: -In a JavaScript program, the correct way to check if an object property is undefined is to use the typeof operator. If the value is not defined, typeof returns the ‘undefined’ string.
Detailed explanation-4: -The undefined property indicates that a variable has not been assigned a value, or not declared at all.
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