We’ve all stumbled on a web page that just doesn’t work. You know the type: the links aren’t clickable, the scrolling is all over the place, and sometimes…they automatically play music. (
So let’s dive in!
A data type is a classification given to different kinds of data used in programming.
seven data types
|Number||Deals with any number, including decimals. You can also do operations (like multiplication, division, etc.) with this data type.|
|String||A string of characters surrounded by single or double quotes.|
|Boolean||Sets a true/false (or yes/no) value.|
|Null||Indicates the intentional absence of a value. Basically means “nothing,” “empty,” or “value unknown.”|
|Undefined||Also indicates the absence of a value. Unlike “null,” “undefined” is usually used when a variable is declared but a value is unassigned.|
|Symbols||Unique identifiers for objects.|
|Object||Collections of related data. Unlike other data types, which can only contain a single thing, objects store collections of data.|
Why Are Data Types Important?
a data type is basically a category of data that can be stored and/or manipulated within a program
The other reason data types are important is because they dictate what you can do with the data you provide—and whether that data will work or not.
For example, if you try to assign a value to a “null” data type, it won’t work because null indicates an empty value! Likewise, there are some data types that only do one thing, like the boolean data type, while others can work with collections of data.
Now that you know what data types are, the typeof function will make more sense: that’s because
In order to use the TypeOf command,
you would write it like you would any operation that uses a single value
(also known as a
). That means the script would look like this:
The syntax would look something like this
, or text, that contains the data type!
Here’s an example of how you might check to see if an object is undefined:
If (typeof object === ‘undefined’)
The TypeOf function is an important tool when dealing with complex code. It allows a programmer to quickly check a variable’s data type—or whether it’s “undefined” or “null”—without going through the code line by line! Additionally, the TypeOf function can also check whether an operand is an object or not.
Depending on the output of the TypeOf function, a programmer can adjust their previous code or quickly pick up where they left off on a project. In other words,
the TypeOf function is a quick way to check data to make sure that a script will work.
What Are the Possible Outputs of the TypeOf Function?
he possible outputs of the TypeOf operator are all data types, too
Here’s a quick summary
of the different type of outputs you might see:
|Boolean (true or false)||“boolean”|
|host objects||Dependent on implementation|
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Check out this expert guide to the classes you should—and shouldn’t—take before you start your college applications.
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