EndsWith

In this medium-level challenge, you'll implement EndsWith<T, U> which checks whether the string type T ends with the substring U, returning true or false.

type a = EndsWith<'abc', 'bc'> // expected to be true
type b = EndsWith<'abc', 'abc'> // expected to be true
type c = EndsWith<'abc', 'd'> // expected to be false

Detailed Explanation

type EndsWith<T extends string, U extends string> = T extends `${string}${U}` ? true : false

How it works:

• Both T and U are constrained to string types with extends string
• T extends \$$`uses a template literal type to check ifTmatches any string followed byU` at the end
• The ${string} wildcard matches zero or more characters at the beginning, so we only care that U appears at the very end of T
• If the pattern matches, the type evaluates to true; otherwise false
• This naturally handles edge cases: an empty string U ('') always matches since ${string}${''} matches any string, while a space ' ' only matches strings that actually end with a space

This challenge helps you understand TypeScript's template literal types and pattern matching for string validation, and how to apply this concept in real-world scenarios.