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Reverse

介绍​

实现类型版本的数组反转 Array.reverse

ts
type a = Reverse<['a', 'b']> // ['b', 'a']
type b = Reverse<['a', 'b', 'c']> // ['c', 'b', 'a']
ts
type a = Reverse<['a', 'b']> // ['b', 'a']
type b = Reverse<['a', 'b', 'c']> // ['c', 'b', 'a']
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起点​

ts
/* _____________ Your Code Here _____________ */
 
type Reverse<T> = any
 
/* _____________ Test Cases _____________ */
 
type cases = [
  Expect<Equal<Reverse<[]>, []>>,
Type 'false' does not satisfy the constraint 'true'.2344Type 'false' does not satisfy the constraint 'true'.
  Expect<Equal<Reverse<['a', 'b']>, ['b', 'a']>>,
Type 'false' does not satisfy the constraint 'true'.2344Type 'false' does not satisfy the constraint 'true'.
  Expect<Equal<Reverse<['a', 'b', 'c']>, ['c', 'b', 'a']>>,
Type 'false' does not satisfy the constraint 'true'.2344Type 'false' does not satisfy the constraint 'true'.
]
ts
/* _____________ Your Code Here _____________ */
 
type Reverse<T> = any
 
/* _____________ Test Cases _____________ */
 
type cases = [
  Expect<Equal<Reverse<[]>, []>>,
Type 'false' does not satisfy the constraint 'true'.2344Type 'false' does not satisfy the constraint 'true'.
  Expect<Equal<Reverse<['a', 'b']>, ['b', 'a']>>,
Type 'false' does not satisfy the constraint 'true'.2344Type 'false' does not satisfy the constraint 'true'.
  Expect<Equal<Reverse<['a', 'b', 'c']>, ['c', 'b', 'a']>>,
Type 'false' does not satisfy the constraint 'true'.2344Type 'false' does not satisfy the constraint 'true'.
]
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解决方案​

Spoiler warning // Click to reveal answer
ts
type Reverse<T extends any[]> = T extends [infer F, ...infer Rest]
  ? [...Reverse<Rest>, F]
  : []
 
 
ts
type Reverse<T extends any[]> = T extends [infer F, ...infer Rest]
  ? [...Reverse<Rest>, F]
  : []
 
 
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