正则+js提取包含嵌套括号内容

Question

需要用正则和js匹配一段内容，该内容是产品配料表，包括名称，括号内备注，和含量百分比。需要提取出每一种配料和百分比。
注意：

1. 目标语言全部是英文，大小写混用
2. 百分比可能是英文逗号做小数点：33,4% 或者33.4% 都有可能
3. 括号里面内容要保留，括号可能出现在百分比前或者后。括号内可能有嵌套
4. 方括号内容都不要
   例子：
   Water 52.64%, sand 13.36% [1], glass12%, concret (-4°-0° brix) 6% [2], grand sand 4.6%, fine added sand (powder, smoke) 0.1%, Sodium sulfate (sodium, calcium, iron (ion), modified glue(FAX)) 4.5%, alkaline sulfides 0.65% (sodium 45%, carbon 0.2%, heptahydrate sodium 0.1%, black stone 0.1%), sulfate ion 0.35%, Potassium sulfate 0.3%, POTAssium chloride 0.3%.

需要得到如下结果：
[ Water 52.64%,
sand 13.36%,
glass12%,
concret (-4°-0° brix) 6%,
grand sand 4.6%,
fine added sand (powder, smoke) 0.1%,
Sodium sulfate (sodium, calcium, iron (ion), modified glue(FAX)) 4.5%,
alkaline sulfides 0.65% (sodium 45%, carbon 0.2%, heptahydrate sodium 0.1%, black stone 0.1%),
sulfate ion 0.35%,
Potassium sulfate 0.3%,
POTAssium chloride 0.3% ]

Answer 1

js的正则不支持balancing group，所以很匹配出嵌套括号的最外层括号，由于正则本身就是状态机实现，所以这里使用状态机的思路完成配料表的提取。
https://www.regular-expressions.info/refrecurse.html
时间复杂度：O(n)
空间复杂度：O(1)，不考虑返回值

function getChargeMixture(str) {
  const ans = []
  let cur = ''
  // lBrackets：左括号数量
  // hasPercentSymbol：是否存在%，只有左括号数量为0时，该值才为true
  // lRectBrackets：左方括号数量
  let lBrackets = 0, hasPercentSymbol = false, lRectBrackets = 0
  for (const ch of str) {
    // 不拼接[xxx]
    if (ch === '[') {
      lRectBrackets++
      continue
    } else if (ch === ']') {
      lRectBrackets--
      continue
    }
    if (lRectBrackets > 0) continue
    if (ch === ',') {
      // 当字符为,并且左括号为0，存在%时，说明获得一种配料，将其加入结果中
      if (lBrackets === 0 && hasPercentSymbol) {
        ans.push(cur.trim())
        cur = ''
        lBrackets  = 0
        hasPercentSymbol = false
        continue
      }
    } else if (ch === '(') {
      lBrackets++
    } else if (ch === ')') {
      lBrackets--
    } else if (ch === '%') {
      // 只要hasPercentSymbol为true了，之后就不会再发生变化
      if (!hasPercentSymbol) hasPercentSymbol = lBrackets === 0
    }
    cur += ch
  }
  cur && ans.push(cur.trim().replace(/\.$/, ''))
  return ans
}

const str = `Water 52.64%, sand 13,36% [1], glass12%, concret (-4°-0° brix) 6% [2], grand sand 4.6%, fine added sand (powder, smoke) 0.1%, Sodium sulfate (sodium, calcium, iron (ion), modified glue(FAX)) 4.5%, alkaline sulfides 0.65% (sodium 45%, carbon 0.2%, heptahydrate sodium 0.1%, black stone 0.1%), sulfate ion 0.35%, Potassium sulfate 0.3%, POTAssium chloride 0.3%.`

console.log(getChargeMixture(str))