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Is variable assignment expensive compared to a null check? For example, is it worth checking that foo is not null before assigning it null?
if (foo != null) {
foo = null;
}
Or is this worrying about nothing?
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Null refers to a value that is either empty or doesn't exist. null means no value. To make a variable null we must assign null value to it as by default in typescript unassigned values are termed undefined. We can use typeof or '==' or '===' to check if a variable is null or undefined in typescript.
In C#, IsNullOrEmpty() is a string method. It is used to check whether the specified string is null or an Empty string. A string will be null if it has not been assigned a value. A string will be empty if it is assigned “” or String.
The typeof operator for undefined value returns undefined . Hence, you can check the undefined value using typeof operator. Also, null values are checked using the === operator.
Use the ISNULL function with the IF statement when you want to test whether the value of a variable is the null value. This is the only way to test for the null value since null cannot be equal to any value, including itself. The syntax is: IF ISNULL ( expression ) ...
This is a micro-micro-optimization (and possibly something handled by the compiler anyways). Don't worry about it. You'll get a far greater return by focusing on your programs actual algorithm.
We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil. -- Donald Knuth
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