js 统计空格次数

Question

var a = ["a","","","","b","","","c",""];
计算后的结果是
{

a:3,
b:2,
c:1

}

Answer 1

var a = ['a', '', '', '', 'b', '', '', 'c', ''];

let b = a.reduce((d, v) => void (v ? (d.k = v) && (d.v[v] = 0) : d.v[d.k] += 1) || d, {v: {}, k: ''}).v;

console.log(b);

Answer 2

((a, _) => a.reduce((p, c) => 
[_ = c || _, _ && [p[_] = p[_] || 0, !c && (p[_] ++)], p][2], {}))
(["a","","","","b","","","c",""], undefined)

会忽略第一个非空字符前的所有空字符。