If, for example, a variable will always store an integer whose value will never exceed 1,000,000, it makes no sense to use an 8-byte double type. Instead, the most efficient type for this data is int, which is a 4-byte integer type that stores data values from –2,147,483,648 to 2,147,483,647.

Declaring a variable or constant with type annotation ensures that the variable or constant stores only data of the appropriate type. JScript has a number of other data types for type annotation. For more information, see Data Type Summary. To add types to JScript, either import an assembly that contains types or declare user-defined types (classes).

Concepts

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