Array js for index in array 하면 index 가 string이라는 거JS Array Usagejs map()js reduce()🕘js filter()js sort()js splicejs every()js some()js slice()js fill()js findIndex(query)js find(filter)js indexOf()js reverse()js join()js shift()js unshift()js pop()js findLast()js findLastIndexjs lastIndexOfjs Array at() JS Array Patternjs array merge JS Array Static MethodsJS Array from()JS Array of()