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[Typescript] 43. Medium - Percentage Parser

typescript 43 Medium parser
2023-09-14 08:59:12 时间

Implement PercentageParser. According to the /^(\+|\-)?(\d*)?(\%)?$/ regularity to match T and get three matches.

The structure should be: [plus or minusnumberunit] If it is not captured, the default is an empty string.

For example:

type PString1 = ''
type PString2 = '+85%'
type PString3 = '-85%'
type PString4 = '85%'
type PString5 = '85'

type R1 = PercentageParser<PString1> // expected ['', '', '']
type R2 = PercentageParser<PString2> // expected ["+", "85", "%"]
type R3 = PercentageParser<PString3> // expected ["-", "85", "%"]
type R4 = PercentageParser<PString4> // expected ["", "85", "%"]
type R5 = PercentageParser<PString5> // expected ["", "85", ""]

 

/* _____________ Your Code Here _____________ */

type PercentageParser<A extends string> = A extends `+${infer N}%` 
  ? ['+', N, '%']
  : A extends `-${infer N}%`
    ? ['-', N, '%']
    : A extends `${infer N}%`
      ? ['', N, '%']
      : A extends `+${infer N}`
        ? ['+', N, '']
        : A extends `-${infer N}`
          ? ['-', N, '']
          : A extends `${infer N}`
            ? ['', N, '']
            : ['', '', '']

type x = PercentageParser<'100%'>
type t = '%' extends '00%' ? true: false
/* _____________ Test Cases _____________ */
import type { Equal, Expect } from '@type-challenges/utils'

type Case0 = ['', '', '']
type Case1 = ['+', '', '']
type Case2 = ['+', '1', '']
type Case3 = ['+', '100', '']
type Case4 = ['+', '100', '%']
type Case5 = ['', '100', '%']
type Case6 = ['-', '100', '%']
type Case7 = ['-', '100', '']
type Case8 = ['-', '1', '']
type Case9 = ['', '', '%']
type Case10 = ['', '1', '']
type Case11 = ['', '100', '']

type cases = [
  Expect<Equal<PercentageParser<''>, Case0>>,
  Expect<Equal<PercentageParser<'+'>, Case1>>,
  Expect<Equal<PercentageParser<'+1'>, Case2>>,
  Expect<Equal<PercentageParser<'+100'>, Case3>>,
  Expect<Equal<PercentageParser<'+100%'>, Case4>>,
  Expect<Equal<PercentageParser<'100%'>, Case5>>,
  Expect<Equal<PercentageParser<'-100%'>, Case6>>,
  Expect<Equal<PercentageParser<'-100'>, Case7>>,
  Expect<Equal<PercentageParser<'-1'>, Case8>>,
  Expect<Equal<PercentageParser<'%'>, Case9>>,
  Expect<Equal<PercentageParser<'1'>, Case10>>,
  Expect<Equal<PercentageParser<'100'>, Case11>>,
]