| function createFibWithMemoization() { | |
| const cached: { [num: number]: number } = {} | |
| return function fib(n: number): number { | |
| if (n <= 1) return n | |
| !cached[n-1] && (cached[n-1] = fib(n - 1)) | |
| !cached[n-2] && (cached[n-2] = fib(n - 2)) | |
| return cached[n-2] + cached[n-1] |
A function is called a higher-order function if its arguments and values are allowed to be functions.
This is an important property that most good programming languages possess.
The composition and tupling operations are examples of functions that take other functions as arguments and return functions as results.
| type Numeral = string | number | |
| function addInt(x: Numeral, y: Numeral): Numeral { | |
| const xx = Number(x) | |
| const yy = Number(y) | |
| const result = xx + yy | |
| if (typeof x === 'string') { | |
| return `${result}` | |
| } | |
| if (typeof x === 'number') { |
| type AnyFuntion = (...args: any[]) => any | |
| type Many<T> = T | ReadonlyArray<T>; | |
| declare const _: _.MyFpImpl | |
| declare namespace _ { | |
| interface MyFpImpl { | |
| compose: FlowRight | |
| } | |
| interface FlowRight { |
| /** | |
| * @param fn - Any function that need to convert to *unary* function | |
| * @returns *unary* function (one parameter function) | |
| * @description `unary` is use to make function, then it can support point-free which 1 parameter | |
| * | |
| * @example | |
| * ```typescript | |
| * // ! DON'T | |
| * console.log(['1', '2', '3'].map( parseInt )) // [1, NaN, NaN] |
| /** | |
| * @description `not` is a function which input any function return boolean and negated its output | |
| * @example | |
| * ```typescript | |
| * function isOdd (x: number) { | |
| * // the possible value of `x % 2` is `0` or `1` | |
| * return x % 2 === 1 | |
| * } | |
| * const isEven = not( isOdd ) | |
| * |
| type Expect<T extends true> = T | |
| type Equal<X, Y> = | |
| (<T>() => T extends X ? 1 : 2) extends (<T>() => T extends Y ? 1 : 2) | |
| ? true | |
| : false | |
| type NotEqual<X, Y> = true extends Equal<X, Y> | |
| ? false | |
| : true |
| type ReturnOf<F> = F extends { (...args: any[]): infer RT } ? RT : never | |
| const value: ReturnOf<String['valueOf']> = 'VALUE'.valueOf() | |
| console.log(value) |
| interface DataEntity { | |
| id: string; | |
| name: string; | |
| } | |
| interface Movie extends DataEntity { | |
| author: string; | |
| } | |
| interface Song extends DataEntity { |
| { | |
| "id": 1, | |
| "subject": "รบกวน Deploy งานให้หน่อยครับ", | |
| "description": "Deploy Staging 21.02.17.R1 ติดแท็กให้ด้วยนะ", | |
| "user": { | |
| "id" 11, | |
| "email": "xyz@example.com", | |
| "firstName": "John", | |
| "lastName": "Doe" | |
| } |