Literal types in TypeScript are a way to specify a value exactly, rather than just a type. Literal types can be used to enforce that a value must be of a specific type and a specific value. Literal types are created by using a literal value, such as a string, number, or boolean, as a type.
For example, the following is a literal type that represents a value of 42:
type Age = 42; let age: Age = 42; // ok let age: Age = 43; // error
In this example, the
Age literal type is created by using the number
42 as a type. This type can then be used to enforce that a value must be of type
number and have the value
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