Bad Code Coding Challenge #40 - To T9 Button Presses

// for context: https://www.reddit.com/r/badcode/comments/hm7ifj/bad_code_coding_challenge_40_to_t9_button_presses/
function to_t9(str) {
    let output = "";
    let firstAllCapsTest = "";
    for(let i = 0; i < str.length; i++) {
        if(str.charAt(i) == str.charAt(i).toUpperCase()) {
            firstAllCapsTest += str.charAt(i);
        }
    }
    let wholeWordUppercase = firstAllCapsTest == str;
    if(wholeWordUppercase) {
        output += "## ";
    }
    str = str.split(" ");
    function getKey(char) {
        char = char.toLowerCase();
        if(char == "0") return "00";
        if(char == "1") return "11111";
        if(char == "2") return "2222";
        if(char == "3") return "3333";
        if(char == "4") return "4444";
        if(char == "5") return "5555";
        if(char == "6") return "6666";
        if(char == "7") return "77777";
        if(char == "8") return "8888";
        if(char == "9") return "99999";
        if(char == "a") return "2";
        if(char == "b") return "22";
        if(char == "c") return "222";
        if(char == "d") return "3";
        if(char == "e") return "33";
        if(char == "f") return "333";
        if(char == "g") return "4";
        if(char == "h") return "44";
        if(char == "i") return "444";
        if(char == "j") return "5";
        if(char == "k") return "55";
        if(char == "l") return "555";
        if(char == "m") return "6";
        if(char == "n") return "66";
        if(char == "o") return "666";
        if(char == "p") return "7";
        if(char == "q") return "77";
        if(char == "r") return "777";
        if(char == "s") return "7777";
        if(char == "t") return "8";
        if(char == "u") return "88";
        if(char == "v") return "888";
        if(char == "w") return "9";
        if(char == "x") return "99";
        if(char == "y") return "999";
        if(char == "z") return "9999";
        if(char == ".") return "1";
        if(char == ",") return "11";
        if(char == "?") return "111";
        if(char == "!") return "1111";
        if(char == "'") return "*";
        if(char == "-") return "**";
        if(char == "+") return "***";
        if(char == "=") return "****";
        return "i did a fucky";
    }
    for(let word of str) {
        let allCapsTest = "";
        for(let i = 0; i < word.length; i++) {
            if(word.charAt(i) == word.charAt(i).toUpperCase() && isNaN(parseInt(word.charAt(i)))) {
                allCapsTest += word.charAt(i);
            }
        }
        let allCaps = false;
        if(allCapsTest == word) {
            allCaps = true;
        }
        if(allCaps && !wholeWordUppercase) {
            if(word.length > 1) output += "## ";
            else output += "# ";
        }
        for(let i = 0; i < word.length; i++) {
            let c = word.charAt(i);
            let key = getKey(c);
            if(c == c.toUpperCase() && isNaN(parseInt(c)) && !allCaps && !wholeWordUppercase && key.charAt(0) != "1" && key.charAt(0) != "*") {
                output += "# ";
            }
            output += key;
            if(i < word.length-1 && getKey(word.charAt(i+1)).charAt(0) == key.charAt(0)) {
                output += "_";
            } else {
                output += " ";
            }
        }
        if(word != str[str.length-1]) output += "0 ";
    }
    return output;
}

// test
console.log(to_t9('Hello World')); //# 44 33 555_555 666 0 # 9 666 777 555 3
console.log(to_t9('HELLO WORLD')); //## 44 33 555_555 666 0 9 666 777 555 3
console.log(to_t9('abba feed high')); //2_22_22_2 0 333_33_33_3 0 44_444_4_44
console.log(to_t9('I love PHP')); //# 444 0 555 666 888 33 0 ## 7 44 7
console.log(to_t9('there r 4 lights!')); //8 44 33 777 33 0 777 0 4444 0 555 444_4_44 8 7777 1111