Split

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题目

The well known split() method splits a string into an array of substrings by looking for a separator, and returns the new array. The goal of this challenge is to split a string, by using a separator, but in the type system!

For example:

type result = Split<"Hi! How are you?", " ">; // should be ['Hi!', 'How', 'are', 'you?']

解答

type Split<S extends string, SEP extends string = never> = [SEP] extends [never]
  ? [S]
  : S extends `${infer F}${SEP}${infer L}`
  ? [F, ...Split<L, SEP>]
  : string extends S
  ? string[]
  : SEP extends ""
  ? []
  : [S];