判斷數組中某個元素的個數

arrCheck(arr) {
		var newArr = [];
		for (var i = 0; i < arr.length; i++) {
			var temp = arr[i];
			var count = 0;
			for (var j = 0; j < arr.length; j++) {
				if (arr[j] == temp) {
					count++;
					arr[j] = -1;
				}
			}
			if (temp != -1) {
				newArr.push(temp + ":" + count)
			}
		}
		return newArr;
	}