join 2 times

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

@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'

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

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?