Great solution, you can use padStart() instead of the ternary for formatTime().

const formatTime = (time: number) :string => time.toString().padStart(2, '0')

The type should be:
('n' | 's' | 'e' | 'w')[]
and not:
string[]

as the description of the test describe.

The solution setup should be:

export function isValidWalk(walk: ('n' | 's' | 'e' | 'w')[]) {

}

In Typescript.
I let a comment on the translation itself: https://www.codewars.com/kumite/5e015677df8a12001d73401f?sel=5e015677df8a12001d73401f

The type should be :
('n' | 's' | 'e' | 'w')[]
and not :
string[]

as the description of the test describe.

The base code should be :

export function isValidWalk(walk: ('n' | 's' | 'e' | 'w')[]) {

}