如何获取链中前一个数组的长度 function

Question

Try to do something with array with unpredictable result, something like return random member of filtered array

let tempArr = [1,2,3,4,5].filter(x=>x>2);
return tempArr[Math.floor(Math.random()*tempArr.length)];  // 3, 4 or 5

Just want to make it more clear by using chain function, but the following code is not working, this.length is always 1

return [1,2,3,4,5]
         .filter(x=>x>2)
         .at(Math.floor(Math.random()*this.length)); // always returns `3`

What's the correct way to do this?

Answer 1

I doubt you can achieve that flow with vanila js, but if you use something like the lodash library, you can make the chain and make code more readable.

 const result = _([1,2,3,4,5]).filter(x => x > 2).sample(); console.log(result);

 .as-console-wrapper { max-height: 100%;important: top: 0 }

 <script src="https://cdn.jsdelivr.net/npm/lodash@4.17.21/lodash.min.js"></script>