Brainfuck interpreter for Codewars kata

brainfuck.js

// Kata url: https://www.codewars.com/kata/my-smallest-code-interpreter-aka-brainf-star-star-k
function brainLuck(code, input) {
    let output = '';
    let pointer = 0
    let input_pointer = 0;
    let storage = {};
    let t = code.length;
    let counter = 0;
    let breakFor = false

    for (let i = 0; i < t; i++) {
        switch(code[i]) {
            case '>':
                ++pointer;
                break;

            case '<':
                if (0 < pointer) {
                    --pointer;
                }
                break;

            case '+':
                if ("undefined" === typeof storage[pointer]) {
                    storage[pointer] = 0;
                }
                storage[pointer] = ++storage[pointer] & 255;
                break;

            case '-':
                if ("undefined" === typeof storage[pointer]) {
                    storage[pointer] = 0;
                }
                storage[pointer] = --storage[pointer] & 255;
                break;

            case '.':
                output += String.fromCharCode(storage[pointer])
                break;

            case ',':
                if ("undefined" === typeof storage[pointer]) {
                    storage[pointer] = 0;
                }
                storage[pointer] = input.codePointAt(input_pointer++);
                break;

            case '[':
                if (!storage[pointer]) {
                    counter = 1;
                    i++;

                    while (counter) {
                        if ('[' == code[i]) {
                            ++counter;
                        } else if (']' == code[i]) {
                            --counter;
                        }
                        i++;
                        if (t <= i) {
                            breakFor = true;
                            break;
                        }
                    }
                    if (breakFor) {
                        breakFor = false;
                        break;
                    }

                    i--;
                }
                break;

            case ']':
                if (storage[pointer]) {
                    counter = 1;
                    i--;

                    while (counter) {
                        if ('[' == code[i]) {
                            --counter;
                        } else if (']' == code[i]) {
                            ++counter;
                        }
                        i--;
                        if (i < 0) {
                            breakFor = true;
                            break;
                        }
                    }
                    if (breakFor) {
                        breakFor = false;
                        break;
                    }

                    i++;
                }
                break;
        }
    }

    return output;
}