TypeScript - Functions - type signature, parameters, return type, variadic functions, rest parameters

Programming TypeScript
Making Your JavaScript Applications Scale
楽天ブックス 紀伊國屋書店

開発環境

• macOS Mojave - Apple (OS)
• Windows 10 Pro (OS)
• Visual Studio Code (Text Editor)
• TypeScript (プログラミング言語)
• Node.js(JavaScriptの実行環境)

Programming TypeScript: Making Your JavaScript Applications Scale (Boris Cherny(著)、O'Reilly Media)のChapter 4(Functions)、Exercises(82)1、2の解答を求めてみる。

コード

TypeScript

console.log('1. both')
console.log('2. arguments object')
let product =  (...numbrs:number[]) :number => numbrs.reduce(
    (prev, curr) => prev * curr)

console.log(product(1, 2, 3, 4, 5, 6, 7, 8, 9, 10))

let numbers:number[] = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

console.log(product(...numbers))

let result = 1;
for (let i = 1; i <= 10; i += 1) {
    result *= i
}
console.log(result)

入出力結果(Bash、cmd.exe(コマンドプロンプト)、Terminal)

$ ts-node sample1.ts 
1. both
2. arguments object
3628800
3628800
3628800
$