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RemoveIndexSignature

介绍​

实现RemoveIndexSignature<T>, 从对象类型中排除索引签名

例如：

ts
  type Foo = {
  [key: string]: any
  foo(): void
}
type A = RemoveIndexSignature<Foo> // expected { foo(): void }
ts
  type Foo = {
  [key: string]: any
  foo(): void
}
type A = RemoveIndexSignature<Foo> // expected { foo(): void }
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起点​

ts
/* _____________ Your Code Here _____________ */
 
type RemoveIndexSignature<T> = any
 
/* _____________ Test Cases _____________ */
 
type Foo = {
  [key: string]: any
  foo(): void
}
 
type Bar = {
  [key: number]: any
  bar(): void
  0: string
}
 
const foobar = Symbol('foobar')
type FooBar = {
  [key: symbol]: any
  [foobar](): void
}
 
type Baz = {
  bar(): void
  baz: string
}
 
type cases = [
  Expect<Equal<RemoveIndexSignature<Foo>, { foo(): void }>>,
Type 'false' does not satisfy the constraint 'true'.2344Type 'false' does not satisfy the constraint 'true'.
  Expect<Equal<RemoveIndexSignature<Bar>, { bar(): void, 0: string }>>,
Type 'false' does not satisfy the constraint 'true'.2344Type 'false' does not satisfy the constraint 'true'.
  Expect<Equal<RemoveIndexSignature<FooBar>, { [foobar](): void }>>,
Type 'false' does not satisfy the constraint 'true'.2344Type 'false' does not satisfy the constraint 'true'.
  Expect<Equal<RemoveIndexSignature<Baz>, { bar(): void, baz: string }>>,
Type 'false' does not satisfy the constraint 'true'.2344Type 'false' does not satisfy the constraint 'true'.
]
 
ts
/* _____________ Your Code Here _____________ */
 
type RemoveIndexSignature<T> = any
 
/* _____________ Test Cases _____________ */
 
type Foo = {
  [key: string]: any
  foo(): void
}
 
type Bar = {
  [key: number]: any
  bar(): void
  0: string
}
 
const foobar = Symbol('foobar')
type FooBar = {
  [key: symbol]: any
  [foobar](): void
}
 
type Baz = {
  bar(): void
  baz: string
}
 
type cases = [
  Expect<Equal<RemoveIndexSignature<Foo>, { foo(): void }>>,
Type 'false' does not satisfy the constraint 'true'.2344Type 'false' does not satisfy the constraint 'true'.
  Expect<Equal<RemoveIndexSignature<Bar>, { bar(): void, 0: string }>>,
Type 'false' does not satisfy the constraint 'true'.2344Type 'false' does not satisfy the constraint 'true'.
  Expect<Equal<RemoveIndexSignature<FooBar>, { [foobar](): void }>>,
Type 'false' does not satisfy the constraint 'true'.2344Type 'false' does not satisfy the constraint 'true'.
  Expect<Equal<RemoveIndexSignature<Baz>, { bar(): void, baz: string }>>,
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
// most popular
 
type RemoveIndexSignature<T, P=PropertyKey> = {
  [K in keyof T as P extends K? never : K extends P ? K : never]: T[K]
}
 
ts
// most popular
 
type RemoveIndexSignature<T, P=PropertyKey> = {
  [K in keyof T as P extends K? never : K extends P ? K : never]: T[K]
}
 
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