javascript - How to operate array [2,4,8] so that it becomes (2 | 4 | 8)

Question

How to operate array [2,4,8] to make it become (2 | 4 | 8)? ?

[2,4,8].join("|") == "2 | 4 | 8", which cannot reach the expected form (2 | 4 | 8).
Tried using join repeatedly ....Can't you add the outer brackets? Please help...

Answer 1

join 2 times

> ['(',')'].join([2, 4, 8].join("|"))
'(2|4|8)'

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@vue_小白

Now we need to convert an array [1,2,4] into a numeric type (1|2|4), because we need to convert the converted (1|2|4) into hexadecimal later... So now I don’t know how to convert the array [1,2,4] into (1|2|4).toString(16) operates like this

The method is as follows:

> arr = [1,2,4]
> arr.reduce((x,y)=>x|y,0).toString(16)
'7'

Answer 2

"(" + [2, 4, 8].join("|") + ")"

Answer 3

1. Wow, if you customize a prototype yourself, the default one cannot be achieved.

var arr = [1, 2, 34];
Array.prototype.FuckJoin = function (start, sp, end) {
  console.log(this);
  var res = start;
  this.forEach(function (a, index) {
    res += a.toString();
    if (arr.length - 1 > index) {
      res += sp.toString();
    }
  })
  return (res + end);
};
console.log(arr.FuckJoin('(', '|', ')'));

2. Isn’t it enough to add a () twice to the string?