1. /**
    2.  * @param {character[]} chars
    3.  * @return {number}
    4.  */
    5. var compress = function (chars) {
    6.     let cur = '',
    7.         index = 0
    9.     for (let i = 0; i < chars.length; i++) {
    10.         if (chars[i] === cur) {
    11.             index += 1
    12.             if (index === 2) {
    13.                 chars.splice(i, 1, index.toString())
    14.             } else if(index > 2) {
    15.                 const strIndex = index.toString()
    16.                 const len = (index - 1).toString().length
    18.                 chars.splice(i - len, len + 1, ...strIndex)
    19.                 i += strIndex.length - len - 1
    20.             }
    21.         } else {
    22.             cur = chars[i]
    23.             index = 1
    24.         }
    25.     }
    27.     return chars.length
    28. };