プログラマー内(javascript)、変数宣言、学習護衛

🏀 私の答え

function solution(a, b) {
    var answer = 0;
    for(let i in a){
        answer += a[i]*b[i];
    }
    return answer;
}

🏀 追加学習

JavaScript変数宣言の場合:

var

var name = 'baskikball'
    console.log(name) // baskikball
var name = 'javascript'
    console.log(name) // javascript

let

  let name = 'baskikball'
    console.log(name) // baskikball
  let name = 'javascript'
    console.log(name) 
    // Uncaught SyntaxError: Identifier 'name' has already been declared

let vs const

 let name = 'baskikball'
    console.log(name) // baskikball
 let name = 'javascript'
    console.log(name) 
    // Uncaught SyntaxError: Identifier 'name' has already been declared
    name = 'durant'
    console.log(name) //durant

const name = 'baskikball'
    console.log(name) // baskikball
const name = 'javascript'
    console.log(name) 
    // Uncaught SyntaxError: Identifier 'name' has already been declared
    name = 'durant'
    console.log(name) 
    //Uncaught TypeError: Assignment to constant variable.

ベイク処理中のvarとletの違い

console.log(foo); // undefined
	var foo;
console.log(bar); // Error: Uncaught ReferenceError: bar is not defined
	let bar;

n/a.結論