What is a Conditional Type?
Explore TypeScript's conditional types to understand how they create types based on conditions using generics and type extensions. Learn to apply nested conditional types for manipulating object members and enforcing strict type constraints, enhancing your advanced TypeScript skills.
A little background on the conditional type
TypeScript 2.8 brings the possibility of the conditional type. The conditional type creates a type by checking if an interface or an existing type extends a type or not. It uses the ternary operator (?:) to get the final type.
Using the conditional type with the dynamic number type
The following code shows a function on line 10 that takes a type T for a parameter. The generic T extends a union of two types defined on lines 1 and 5.
The function returns the object itself and puts the educational goal on the front instead. What is important is the return type on line 10: a type that uses the ...