Solving Valid Parantheses - Leetcode problem

Problem Statement

Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.

Leetcode link - https://leetcode.com/problems/valid-parentheses/

Idea

We can use stack to keep track of the opening brackets and ensures that they are matched correctly with their corresponding closed brackets.

Pseudo Code

Loop through the String and for each element:
    If the  element exists in the opening brackets array:
        Insert it into the stack.
    ELSE:
        Get the top element from the stack and compare.
        IF matching, continue.
        ELSE return false.
End Loop

If Stack is not empty then return false

Time Complexity: O(N)
Space Complexity: O(N) // because of the stack

Implementation

/**
 * @param {string} s
 * @return {boolean}
 */
var isValid = function(s) {
    let stack = new Array();
    let map = {
        "(":")",
        "[":"]",      
        "{":"}",
    }

    for(let i=0; i<s.length; i+=1) {
        // console.log({stack})
        if(['(', '[', '{'].includes(s[i])) {
            stack.push(s[i]);
        } else {
            let last = stack.pop();
            if(map[last] !== s[i]) {
                return false;
            }
        }
    }
    if(stack.length > 0) return false;
        return true;
};