Answer 1

function normalize(s) {
    let arr = s.match(/w+/g)
    let result
    while(arr.length) {
        let cur = arr.pop()
        let temp = {value: cur}
        if(result) {
            temp.children = result
        }
        result = temp
    }
    return result
}


// 测试
var s = 'abc'
normalize(s) // {value: "abc"}

s = '[abc[bcd[def]]]'
normalize(s) 
// {value: 'abc', children: {value: 'bcd', children: {value: 'def'}}}

更过编程算法题可见 JavaScript-Algorithms

Answer 2

万能的 prototype，js 天生的 middleware，赞一个！