Generate-Parentheses2.js

/**
 * @param {string} str
 * @return {boolean}
 */
const isValid = function(str) {
    const arr = [];
    const map = {
        "}": 1,
        ")": 2,
        "]": 3,
    }
    for(let item of str){
       if(item === '{'){
          arr.push(1);
       }else if(item === '('){
          arr.push(2);
       }else if(item === '['){
          arr.push(3);
       }else{
           if(arr.pop() !== map[item] ){
              return false;
           }
       }
    }
    return arr.length === 0;
};