Javascript Algorithm String Parenthesis match 2

class Stack {/*from   w ww  . j av  a 2  s.c o  m*/

    constructor () {
        this.items = [];
    }

    push(element){
        this.items.push(element);
    }

    pop(){
        return this.items.pop();
    }

    peek(){
        return this.items[this.items.length-1];
    }

    isEmpty(){
        return this.items.length == 0;
    }

    size(){
        return this.items.length;
    }

    clear(){
        this.items = [];
    }

    print(){
        console.log(this.toString());
    }

    toString(){
        return this.items.toString();
    }
}
function parenthesesChecker(symbols){

    let stack = new Stack(),
        balanced = true,
        index = 0,
        symbol, top,
        opens = "([{",
        closers = ")]}";

    while (index < symbols.length && balanced){
        symbol = symbols.charAt(index);
        if (opens.indexOf(symbol) >= 0){
            stack.push(symbol);
            console.log(`open symbol - stacking ${symbol}`);
        } else {
            console.log(`close symbol ${symbol}`);
            if (stack.isEmpty()){
                balanced = false;
                console.log('Stack is empty, no more symbols to pop and compare');
            } else {
                top = stack.pop();
                //if (!matches(top, symbol)){
                if (!(opens.indexOf(top) === closers.indexOf(symbol))) {
                    balanced = false;
                    console.log(`poping symbol ${top} - is not a match compared to ${symbol}`);
                } else {
                    console.log(`poping symbol ${top} - is is a match compared to ${symbol}`);
                }
            }
        }
        index++;
    }
    if (balanced && stack.isEmpty()){
        return true;
    }
    return false;
}

console.log(parenthesesChecker('{([])}')); //true
console.log(parenthesesChecker('{{([][])}()}')); //true
console.log(parenthesesChecker('[{()]')); //false