Check out example codes for "typescript convert an unknown to string". It will help you in understanding the concepts better.

Code Example 1

// To convert an unknown type into any other type we can use assertions


let demo: unknown = 'Rice Krispies';
// The above line would throw an error as an unknown variable can 
// only take values of unknown and any type

let demo: unknown = 'The EXTRA cripsy colonel...' as string;

// the as string assertion allows us to set an unknown type to a string type
// This can be done with any other variable types it is not 
// limited to string

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