This lesson explains the ReturnType mapped type.

Extracting the return type of a function

In some cases, you may want to extract the returned type of a function. TypeScript comes with a ReturnType mapping function that gives you this information.

For example, if you have a function that returns a string, you can use ReturnType<yourFunction> and it will return the type string. The following code on line 5 assigns to a variable, the type which is a string because the return type of the function getName is a string.

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