请问如何计算数组中不同元素个数?

Question

预期: arr = ['1','2','3','3'] = > 输出3
预期: arr = ['1','1','1','3'] = > 输入2

Answer 1

console.log([...new Set([5,5,6,6,8,])].length)数组去重便可得到不同元素的个数, 具体看看数组去重的几种方法