To better understand casting its worth reading about data types first.
So if data types define the type of data computers store, casting is converting data from one type to another.
Use Cases and Examples
Computers recognize different types of data. For example, text is identified as
But one thing that does not translate into the real world is that numbers can be converted to strings as well. Meaning the computer will treat the number like its text.
Once a number becomes a string, you can append it to other numbers or text.
Here is an example of the difference between adding numbers and adding numbers that have been cast into strings.
// adding numbers together console.log(2 + 2) // 4 // adding numbers converted to strings together console.log(String(2) + String(2)) // 22 // adding a number and a number converted to string together console.log(String(2) + 2) //22
The first example shows the results you get back from adding 2 and 2 together, resulting in a
4 as expected.
In the second example, we convert both numbers to strings using the function
String() now, instead of adding the numbers together, 2 is appended to the second 2 resulting in
+ is now acting as a glue, putting both numbers together in a process known as concatenation.
Casting can be performed between many data types, but you might end up with an undesired result sometimes. For example, what do you get if you try to cast a string to a number?
parseInt("some text") // NaN.
Other programming languages interpret this differently.All terms