tower-of-babel

arrow-function.js

'use strict';
// 変数 a はblockスコープの中でも外でも再代入可能な有効な変数です。変数宣言の方法(var|let|const)のいずれを利用するべきか検討してください
var a = 5;

// 変数 b は再代入不可能な変数です。変数宣言の方法(var|let|const)のいずれを利用するべきか検討してください
const b = process.argv[2];

if (a === 5) {
  // ここでの変数 c は再代入可能ですが、このblockの中でだけ有効な変数です。変数宣言の方法(var|let|const)のいずれを利用するべきか検討してください。
  let c = 4;
  console.log(c);  // 4

  // ここでの変数 b はblockの中だけで有効な変数です。変数宣言の方法(var|let|const)のいずれを利用するべきか検討してください。
  let b = 8;
  console.log(b); // 8
}

console.log(a); // 5
console.log(b);
try {
  // ここで cに対して値を変更してみましょう。
  c = 1000;
} catch (e) {
  // c is not defined エラーが発生することを確認して下さい。
  console.log(e);
}

class-extends.js

class Character {
  constructor(x, y){
    this.x = x;
    this.y = y;
    this.health_ = 100;
  }

  damage() {
    this.health_ -= 10;
  }

  getHealth() {
    return this.health_;
  }

  toString() {
    return `x: ${this.x} y: ${this.y} health: ${this.getHealth()}`
  }
}

class Player extends Character {

  constructor(x, y, name) {
    super(x, y);
    this.name = name;
  }

  move(dx, dy) {
    this.x += dx;
    this.y += dy;
  }

  toString() {
    return `name: ${this.name} ${super.toString()}`
  }

}

var [,,x, y, name] = process.argv;
var character = new Character(+x, +y);
character.damage();
console.log(character.toString());

var player = new Player(+x, +y, name);
player.damage();
player.move(7, 8);
console.log(player.toString());

class.js

class Character {
  constructor(x, y){
    this.x = x;
    this.y = y;
    this.health_ = 100;
  }

  damage() {
    this.health_ -= 10;
  }

  getHealth() {
    return this.health_;
  }

  toString() {
    return `x: ${this.x} y: ${this.y} health: ${this.getHealth()}`
  }
}

var [,,x, y] = process.argv;
var character = new Character(+x, +y);
character.damage();
console.log(character.toString());

computed-property.js

var obj = {
  [+process.argv[2] % 2 === 0 ? "even" : "odd"]: +process.argv[2],
  [+process.argv[3] + +process.argv[2]]: +process.argv[3] + +process.argv[2]
};
console.log(obj);

destructure.js

var json = {
  "name": {
    "first": "Yosuke",
    "family": process.argv[2]
  },
  "birth": {
    "year": 1982,
    "month": 12,
    "day": process.argv[3]
  }
};
// ここでデストラクチャリングを使ってname.familyをfamilyNameに。
// birth.day を birthDay に束縛してください。
let {name:{family:familyName},birth:{day:birthDay}} = json;


console.log(familyName);
console.log(birthDay);

generator.js

const max = +process.argv[2];

let FizzBuzz = function*(){
  let count = 0;
  while (count < max) {
    count += 1;
    let result = count;
    if (count % 15 === 0) result = 'FizzBuzz';
    if (count %  3 === 0) result = 'Fizz';
    if (count %  5 === 0) result = 'Buzz';
    yield result;
  }
}();

for (var result of FizzBuzz) {
  console.log(result);
}

iterator-for-of.js

const max = process.argv[2];
let FizzBuzz = {
  [Symbol.iterator]() {

    let count = 0;

    return {
      next() {
        count += 1;
        let result = count;
        if (count % 3 === 0)
          result = 'Fizz';
        if (count % 5 === 0)
          result = 'Buzz';
        if (count % 15 === 0)
          result = 'FizzBuzz';
        return {
          done: count <= max ? false : true,
          value: result
       }
      }
    };
  }
}

for (var n of FizzBuzz) {
  console.log(n);
  // 1
  // 2
  // Fizz
  // 4
  // Buzz
  // Fizz
  // 7
  // 8
  // Fizz
  // Buzz
  // 11
  // Fizz
  // 13
  // 14
  // FizzBuzz
  // 16
  // 17
  // Fizz
  // 19
  // Buzz
  // Fizz
  // 22
  // 23
  // Fizz
  // Buzz
  // 26
  // Fizz
  // 28
  // 29
  // FizzBuzz
  // ...
}

modules-default-export-main.js

var arg1 = process.argv[2];
var arg2 = process.argv[3];

import Math from './modules-default-export-math';
console.log(Math.PI);
console.log(Math.sqrt(+arg1));
console.log(Math.square(+arg2));

modules-default-export-math.js

const PI = 3.141592;

var _sqrt = function(s, x, last){
  return x != last ? _sqrt(s, (x + s / x) / 2.0, x) : x;
};
const sqrt = function(s){
  return _sqrt(s, s/2.0, 0.0);
};
const square = function(x){
  return x * x;
};

export default {
  PI, sqrt, square
}

modules-with-name-main.js

var arg1 = process.argv[2];
var arg2 = process.argv[3];

import {PI, sqrt, square} from './modules-with-name-math';

console.log(PI);
console.log(sqrt(+arg1));
console.log(square(+arg2));

modules-with-name-math.js

export const PI = 3.141592;

var _sqrt = function(s, x, last){
  return x != last ? _sqrt(s, (x + s / x) / 2.0, x) : x;
};
export let sqrt = function(s){
  return _sqrt(s, s/2.0, 0.0);
};
export let square = function(x) {
  return x * x;
};

program.js

var arg = process.argv[2];
console.log(`Hello ${arg}`);

rest-and-spread.js

var args = process.argv[2].split(",");
args = args.map((arg)=> +arg);

// ここに平均を取るavg関数を作る、作る際には
// RESTパラメータを利用すること。
let avg = (...nums) => {
  return nums.reduce((p, c) => p + c) / nums.length;
};
console.log(avg(...args));