Simple kata for finding if a string has balanced braces (no other characters). Solves a simple programming interview question a friend had to do.

braceBalanceChecker.js

function isArrayBalanced(inputArray) {
    function isBalanced(input) {
        Array.prototype.peek = function() {
            return this[this.length - 1];
        };
        if (input.length % 2 !== 0) return "NO";
        var braceStack = [];
        var braceMap = {
            "}" : "{",
            "]" : "[",
            ")" : "("
        };
        var closingBraces = "}])", openingBraces = "{[(";

        for (var i = 0; i < input.length; i++) {
        // input.forEach(function(character){
            if (openingBraces.indexOf(input[i]) > -1) {
                braceStack.push(input[i]);
            }
            if (closingBraces.indexOf(input[i]) > -1) {
                if(braceStack.peek() === braceMap[input[i]]) {
                    // This is good, everything matches
                    // pop the stack and continue
                    braceStack.pop();
                } else {
                    return "NO";
                }
            }
        };

        if (braceStack.length > 0) return "NO";
        return "YES";
    }
    var newArr = [];
    inputArray.forEach(function(input){
        newArr.push(isBalanced(input));
    });

    return newArr;
}

console.log(isArrayBalanced(["[()]", "[]", "[[]]]", "({[}])"]));