Message Translator (FinalExam 071219)

function solve(input){

let count = Number(input.shift());
let isValid = false;
let command = '';
let message = '';

const decypher = (msg)=>{
    let arr = msg.split('');
    return arr.map(item=>{
        return item.charCodeAt();
    }).join(' ');
};


const stripEnds = (string)=>{
    return string.substring(1,string.length-1);
}


const lineValid = (line)=>{
    return line.includes('!:[');
}

const commandLineValid = (commandLine)=>{
    return (commandLine.startsWith('!') && commandLine.endsWith('!'));
}

const onlyLowerCase = (word)=>{
    for (const letter of word) {
        if(letter.charCodeAt()<97 || letter.charCodeAt()>122){
            return false;
        }
    }
    return true;
}

const commandValid = (command)=>{
    if((command[0].charCodeAt()>=65 && command[0].charCodeAt()<=90) && onlyLowerCase(command.substring(1)) && command.length>=3 ){
        return true;
    }else{
        return false;
    }
}

const isOnlyAlphabetical = (string)=>{
    for (const letter of string) {
        if((letter.charCodeAt() < 65 || letter.charCodeAt() > 122) || (letter.charCodeAt() > 90 && letter.charCodeAt() < 97)){
            return false;
        }
    }
    return true;
}


const isValidMessageLine = (line)=>{
    return (line.startsWith('[') && line.endsWith(']'))
}

const messageIsValid = (message) =>{
    return (isOnlyAlphabetical(message) && message.length>=8);
}



for (const line of input) {
    if(lineValid(line)){
       let [commandLine, messageLine] = line.split(':');
       if(commandLineValid(commandLine) && isValidMessageLine(messageLine)){
             command = stripEnds(commandLine);
             message = stripEnds(messageLine);
        if(commandValid(command) && messageIsValid(message)){
            isValid = true;

        }
       }
    }


    console.log( isValid === false ? `The message is invalid` : `${command}: ${decypher(message)}`);
    isValid = false;
}

}