CODEWITHSUNDEEP
javascriptarraysalgorithmmethods
KeoFoxy
KeoFoxy

Reputation: 51

Array methods do not work inside .map JavaScript

Noob is looking for help. I have a function that takes a string of braces and check if it follows some rules

"(){}[]"   =>  True
"([{}])"   =>  True
"(}"       =>  False
"[(])"     =>  False
"[({})](]" =>  False

Solution is simple: keep adding to result array a left braces till you face a right braces(I add it to an array and then slice them) but when I want to slice or pop 2 last elements of the result array it doesnt work

function validBraces(braces){
    return [...braces].map((currentBrace,index) => {
        let result = []
        if(currentBrace == '{' | currentBrace == '(' | currentBrace == '['){
            result += (currentBrace) //If I use push I get as a result [ [], [], etc.]
        }

        if(currentBrace == ')' | currentBrace == ']' | currentBrace == '}'){
            result.slice(0, -2)
        }

        return result//.length == 0 ? true : false
    })

}

How I can slice an array of elements inside this function?

Upvotes: 0

Views: 49

Answers (1)

Anonymous Camel
Anonymous Camel

Reputation: 23

Your code is doing as it shoul, it is just that you are returning a mapped array (array.map() returns an array). currentBrace does not carry between iterations, so you are slicing nothing. If you wanted it to be a bool, iterate through the array, like:

function validBraces(str) {
    let [open,close,stack]=[['[','{','('],[']','}',')'],""];
    for (var i of str) {
        //if it is an opening brace
        if (['[','{','('].includes(i)) stack+=i;
        //if it is a closing and matches the last one in the stack 
        else if (open.indexOf(stack[stack.length-1])==close.indexOf(i)) {
            stack=stack.slice(0,-1);
        } else return false;
    }
    return stack.length==0;
}

Upvotes: 2

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