Type Constructors
This lesson explains theoretical foundations of generic types and gives you a glimpse into category theory. It provides a mental model that will prove useful in the next chapters.
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Two worlds
Type constructor is a function (not a regular function, a mathematical function) that takes a type and returns a new type (based on the original type).
Notice that a generic interface with only one type argument is exactly that. For example, the FormField type from the previous lesson is a function with one type argument, T. It takes a type (e.g. string) and returns a new type (FormField<string> or { value?: string; defaultValue: string; isValid: boolean; }).
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