javascript concat(), const

참고 https://msdn.microsoft.com

const의 사용 예

qiita.rb

var c = 10;
{
    const c = 2;
   // At this point, c = 2.
}
// At this point, c = 10.

// Additional ways to declare a variable using const.
const name = "Thomas Jefferson";
const answer = 42, numpages = 10;
const myarray = new Array();

concat()은 배열을 조합한다

qiita.rb

var a, b, c, d;
a = new Array(1,2,3);
b = "dog";
c = new Array(42, "cat");
d = a.concat(b, c);
document.write(d);

//Output: 
1, 2, 3, "dog", 42, "cat"