let getTriangle = function(base, height){
return base * height / 2;
};
↓ => 記法で記述します
let getTriangle = (base, height) => {
return base * height / 2;
};
↓ 1行にして一番最後のセミコロンを省略します
let getTriangle = (base, height) => { return base * height / 2; }
↓ return と {} を省略します
let getTriangle = (base, height) => base * height / 2
let getTriangle3 = (base, height) => { base * height / 2; }
console.log('三角形の面積は' + getTriangle3(3,4));
↓ 結果
三角形の面積はundefined